We are giving the classic bistro “Steak Frites” a serious upgrade by using tender lamb sirloin steak and a zesty, chilled green peppercorn labneh that cuts right through the richness.
It is the kind of meal that feels fancy enough for a Saturday night but is straightforward enough to master in your own kitchen. You get that perfect, pan-seared crust on the lamb, the crunch of double-fried rosemary fries, and a bright celery apple salad to keep everything feeling fresh. Let’s get cooking!
Jump to:
Why We Love the Recipe
- The “Better” Sauce: Labneh provides a creamy, probiotic-rich base that feels indulgent without the heaviness of traditional steak sauces.
- Double-Fried Crunch: The two-stage frying process ensures your rosemary fries stay crispy on the outside and fluffy on the inside.
- Skill Builder: You'll practice fat-rendering and butter-basting, which are the secrets to restaurant-quality meat at home.
Ingredients
The Lamb
- Lamb sirloin steaks
- Kosher salt
- Black pepper
- Neutral oil
- Butter
- Garlic cloves
- Fresh thyme
Green Peppercorn Labneh
- Labneh or thick Greek yogurt
- Green peppercorns in brine
- Brine from the peppercorns
- Lemon zest
- Lemon juice
- Olive oil
- Garlic clove
- Salt
Rosemary Fries
- Russet potatoes
- Neutral frying oil (canola, peanut, or sunflower)
- Kosher salt
- Fresh rosemary
For Serving
See recipe card below for exact quantities.
Instructions
Make the Green Peppercorn Labneh Sauce
In a small bowl, whisk together the labneh, crushed peppercorns, brine, zest, juice, oil, garlic, and salt. Refrigerate until serving; it gets better as the flavours mingle.
Cut, Rinse and Dry Potatoes
Cut potatoes into ⅜″ (1 cm) thick fries. Rinse them in cold water to remove excess starch. Soak for 10 minutes, then drain and dry thoroughly with towels. Pro tip: Surface moisture is the enemy of crunch; ensure they are bone dry before frying.
Rosemary Fries – The First Fry (The Soften)
Heat oil over medium-low heat until it reaches 300°F (150°C). If you don’t have a thermometer, the oil is ready when a single test fry produces slow, gentle bubbles. Fry for 4 to 5 minutes until softened but still pale. This “blanching” step cooks the potato from the inside out.
Remove and drain on a rack. Crucial Step: Let them rest and cool for at least 10 minutes to allow the starch to set.
Season and Sear the Lamb
If your lamb has a particularly thick fat cap, trim it down to less than a ¼″ and score diagonally, trying not to cut into the meat. If you prefer to keep the fat cap as is, see The “Cold Start” for Fat Rendering instructions.
Season the room temperature lamb with salt and pepper.
Heat a heavy skillet over medium-high heat with the neutral (high smoke point) oil. You want the pan surface at 425°F to 450°F (218°C to 232°C). The oil should be shimmering and just starting to show a faint wispy smoke. Sear in batches of two to prevent overcrowding and steaming. Place the lamb fat-cap down for 3 to 4 minutes to render. Flip and cook 2 to 3 minutes for a crust. You should hear a steady, active sizzle. If it sounds violent or looks smoky, turn the heat down slightly.
Place the steaks on a sheet pan. Remove all but 1-2 tablespoons of the pan drippings.
Butter Baste The Lamb
Reduce the heat to medium (aiming for a pan temp of 350°F to 375°F / 177°C to 190°C). This is crucial! You want the butter to foam and smell nutty, not turn black and bitter.
Add butter, garlic and thyme. Once the butter melts, return all four steaks to the pan. Spoon foaming butter over the steaks for 2 to 3 minutes until the internal temp hits 125°F to 128°F (52°C to 53°C). Rest for 8 minutes, uncovered on a wooden board or warm plate.
Rosemary Fries – The Second Fry (The Crisp)
Increase heat to medium-high until oil reaches 375°F (190°C). The oil should be shimmering and a test fry should sizzle vigorously immediately. Fry for 6 to 8 minutes until golden. This high heat creates a rigid, golden crust. Place the fries onto a sheet pan with a rack to let any extra oil drip off. Then transfer to a bowl and immediately toss with rosemary and salt.
For Serving
Slice the lamb against the grain.
Plate over a dollop of labneh green peppercorn sauce and serve with a side of hot rosemary fries and a crispy Celery-Apple Salad.
Zimmy's Pro-Tips for the Perfect Lamb Sirloin
Essential Tools
- Invest in an Instant-Read Meat Thermometer: When you're cooking lamb sirloin, 5 degrees is the difference between juicy medium-rare and overdone. A digital instant-read thermometer allows you to check the thickest part of the steak in seconds. For this recipe, pull the lamb at 125°F to 128°F; it will continue to rise as it rests.
- Oil Temperature is Non-Negotiable: For the fries, use a clip-on candy or deep-fry thermometer. If the oil is too cool, the potatoes will soak up grease and become heavy. If it's too hot, the outside will burn before the inside is fluffy. Keep the oil steady at 300°F for the first fry and 375°F for the second for perfect results.
Cooking Techniques
- The "Cold Start" for Fat Rendering: If your lamb has a thick fat cap, you can trim it down like we did, or place it fat-side down in a cold skillet and then turn the heat to medium-high. This allows the fat to gradually render as the pan heats, creating a crispier edge without overcooking the center.
- Don’t Crowd the Pan: If you are cooking all four steaks at once, make sure your skillet is large enough. If they touch, they'll steam instead of sear and you'll lose that beautiful golden crust. Work in batches if necessary.
- The Water Drop Test: If you don’t have an infrared thermometer for your skillet, flick a small drop of water onto the dry pan. If it dances and skitters across the surface before evaporating, the pan is at the ideal searing temperature of roughly 400°F to 450°F.
Resting & Slicing
- Let It Breathe: When resting the lamb, do not tent it tightly with foil. This traps steam and softens the crispy fat cap. Instead, leave it on a warm plate or wooden board; the meat is dense enough to retain heat during the 8-minute rest.
- Why Slice Against the Grain: Look for the long muscle fibers in the lamb and slice perpendicular to them. This shortens the fibers, making each bite tender rather than stringy.
Mastering Your Equipment
- Learn Your Burners: Every stove is different. If you’re using a heavy cast-iron skillet, remember that it holds heat extremely well. You may find that "Medium" on your stove behaves more like "Medium-High." Use a thermometer the first few times to calibrate your heat control.
FAQs About Lamb Sirloin
A: Think of the lamb sirloin as the “pantry staple” of the lamb world. It is a lean, tender cut taken from the leg. Unlike a rib chop, it is usually boneless and has a consistent thickness, which makes it incredibly easy to sear just like a high-quality beef steak. It has a rich, earthy flavour that isn’t overly “gamey,” making it a perfect entry point if you are new to cooking lamb.
A: For the best experience, aim for medium-rare. You want to pull the lamb off the heat when it hits an internal temperature of 125°F to 128°F (52°C to 53°C). As it rests, the temperature will naturally climb to about 130°F to 135°F (54°C to 57°C). This keeps the meat juicy and prevents it from becoming tough or chewy.
A: The secret is starting the lamb “fat-side down” in a medium-high pan before you even worry about the flat sides of the steak. This “renders” the fat (melts it down), turning it into a golden, crispy deliciousness. If the fat layer looks thick, give it a quick score with a sharp knife first, just don’t cut into the actual meat!
A: You certainly can, but you don’t have to. Because the sirloin is naturally tender, a generous coating of kosher salt and cracked pepper is often all you need, especially when you are finishing it with a butter-baste of garlic and thyme. If you want a deeper flavour, a quick 30-minute rub of olive oil, lemon zest, and rosemary works wonders.
A: Since lamb is naturally rich, you want sides that offer a “crunch” and a bit of “zip.”
• The Crunch: Our Rosemary Fries provide that salty, earthy base.
• The Zip: A bright, acidic side like my Celery-Apple Salad is the perfect palate cleanser to cut through the buttery lamb as well as our fresh Green Peppercorn Labneh sauce.
Equipment Used: This Lamb Sirloin Steak Frites recipe was made in collaboration with Hestan Culinary. We used the NanoBond 12.5″ Skillet and Dutch Oven along with their Provisions Mixing Bowls and Sheet Pans for prep and serving. All opinions in this post are always my own.
Love this Lamb Steak Recipe? Try These Next:
- Slow Roasted Greek Lamb Shoulder with Roasting Pan Potatoes
- Charcoal Grilled Lamb Lollipops with Herb-Garlic Sauce
- Gochujang Honey Glazed Leg of Lamb
- Grilled Lamb Chops with Poblano Board Sauce
📖 Recipe
Lamb Sirloin Steak Frites with Green Peppercorn Sauce
Equipment
- Instant-Read Meat Thermometer for the steak
- A clip-on candy or deep-fry thermometer for the fries
Ingredients
The Lamb
- 4 lamb sirloin steaks fat trimmed down and scored, room temperature (6 to 7 oz / 170 to 200 g each)
- 1 teaspoon kosher salt
- ½ teaspoon freshly cracked black pepper
- 1 tablespoon neutral oil or rendered lamb fat
- 2 tablespoon butter unsalted
- 2 garlic cloves lightly crushed
- 3 sprigs fresh thyme
Green Peppercorn Labneh
- ¾ cup labneh or thick Greek yogurt
- 1 tablespoon green peppercorns in brine lightly crushed
- 1 teaspoon brine from the peppercorns
- 1 teaspoon lemon zest
- 1 tablespoon lemon juice
- 1 tablespoon olive oil
- 1 small garlic clove finely grated
- Pinch salt
Rosemary Fries
- 2 lbs russet potatoes 900 g
- 8 cups Neutral frying oil (canola, peanut, or sunflower) about 2 L
- 1 teaspoon kosher salt
- 1 teaspoon finely chopped fresh rosemary
For Serving
Instructions
Make the Green Peppercorn Labneh Sauce
- In a small bowl, whisk together the labneh, crushed peppercorns, brine, zest, juice, oil, garlic, and salt. Refrigerate until serving; it gets better as the flavours mingle.
Cut, Rinse and Dry Potatoes
- Cut potatoes into ⅜″ (1 cm) thick fries. Rinse them in cold water to remove excess starch. Soak for 10 minutes, then drain and dry thoroughly with towels. Pro tip: Surface moisture is the enemy of crunch; ensure they are bone dry before frying.
Rosemary Fries – The First Fry (The Soften)
- Heat oil over medium-low heat until it reaches 300°F (150°C). If you don’t have a thermometer, the oil is ready when a single test fry produces slow, gentle bubbles. Fry for 4 to 5 minutes until softened but still pale. This “blanching” step cooks the potato from the inside out. Remove and drain on a rack. Crucial Step: Let them rest and cool for at least 10 minutes to allow the starch to set.
Trim, Season & Sear the Lamb
- If your lamb has a particularly thick fat cap, trim it down to less than a ¼″ and score diagonally, trying not to cut into the meat. If you prefer to keep the fat cap as is, see The “Cold Start” for Fat Rendering instructions.
- Season the room temperature lamb with salt and pepper.
- Heat a heavy skillet over medium-high heat with the neutral (high smoke point) oil. You want the pan surface at 425°F to 450°F (218°C to 232°C). The oil should be shimmering and just starting to show a faint wispy smoke. Sear in batches of two to prevent overcrowding and steaming. Place the lamb fat-cap down for 3 to 4 minutes to render. Flip and cook 2 to 3 minutes for a crust. You should hear a steady, active sizzle. If it sounds violent or looks smoky, turn the heat down slightly.
- Place the steaks on a sheet pan. Remove all but 1-2 tablespoons of the pan grease.
Butter Baste The Lamb
- Reduce the heat to medium (aiming for a pan temp of 350°F to 375°F / 177°C to 190°C). This is crucial! You want the butter to foam and smell nutty, not turn black and bitter. Add butter, garlic, and thyme. Once the butter melts, return all four steaks to the pan. Spoon foaming butter over the steaks for 2 to 3 minutes until the internal temp hits 125°F to 128°F (52°C to 53°C). Rest for 8 minutes, uncovered on a wooden board or warm plate.
Rosemary Fries – The Second Fry (The Crisp)
- Increase heat to medium-high until oil reaches 375°F (190°C). The oil should be shimmering and a test fry should sizzle vigorously immediately. Fry for 6 to 8 minutes until golden. This high heat creates a rigid, golden crust. Place the fries onto a sheet pan with a rack to let any extra oil drip off. Then transfer to a bowl and immediately toss with rosemary and salt.
For Serving
- Slice the lamb against the grain. Plate over a dollop of labneh green peppercorn sauce and serve with a side of hot rosemary fries and a crispy celery-apple salad.
💬Tried this recipe?
- We'd really appreciate a rating and quick review! It helps more home cooks find the recipe, and we love hearing what you think.
Video
Notes
Zimmy’s Pro-Tips for the Perfect Lamb Sirloin
- Invest in an Instant-Read Meat Thermometer: When you’re cooking lamb sirloin, 5 degrees is the difference between juicy medium-rare and overdone. A digital instant-read thermometer allows you to check the thickest part of the steak in seconds. For this recipe, pull the lamb at 125°F to 128°F; it will continue to rise as it rests!
- Oil Temperature is Non-Negotiable: For the fries, use a clip-on candy or deep-fry thermometer. If the oil is too cool, the potatoes will soak up the grease and become heavy. If it’s too hot, the outside will burn before the inside is fluffy. Keeping it steady at 300°F for the first fry and 375°F for the second is the secret to success.
- The "Cold Start" for Fat Rendering: If your lamb has a particularly thick fat cap you can trim it down like we did, or you can place it fat-side down in a cold skillet, then turn the heat to medium-high. This allows the fat to melt (render) gradually as the pan heats up, resulting in a much crispier edge without overcooking the meat center.
- Don't Crowd the Pan: If you are cooking all four steaks at once, make sure your skillet is large enough. If they are touching, they will steam instead of sear, and you’ll lose that beautiful golden crust. Work in batches if you need to!
- Let It Breathe: When resting the lamb, do not tent it tightly with foil. This traps steam and will turn your perfectly crispy fat cap soft. Simply leave it on a warm plate or a wooden board; the meat is dense enough to hold its heat for those 8 minutes.
- Why Against the Grain? Look for the long muscle fibers in the lamb. Slice perpendicular to them. This "shortens" the fibers, making every bite melt-in-your-mouth tender rather than stringy.
- Learn Your Burners: Every stove is different. If you’re using a stainless steel skillet, remember that it holds heat incredibly well. You may find that "Medium" on your stove actually acts like "Medium-High." Use a thermometer to "calibrate" your senses the first few times you cook this!
- The Water Drop Test: If you don't have an infrared thermometer for your skillet, flick a tiny drop of water onto the dry pan. If the water dances and skitters across the surface before evaporating, you’ve hit that perfect searing temperature of roughly 400°F to 450°F.
Leave a Reply