Combine the onions and the chopped rosemary in a small bowl, sprinkle with salt & pepper, then pour the olive oil over the onions stir to combine the seasoning and set aside on the counter for at least 30 minutes up to 4 hours.
Preheat your pizza oven, grill or oven. (Pizza oven 800°F/425°C, Grill to 450°F/230°C, Oven to 425°F/220°C)
In a skillet over medium-low heat, add the rosemary sprigs and butter. Melt the butter and bruise the rosemary with a wooden spoon to bring out the flavour. Cook for 1 minute, then add the pears in a single layer. If your skillet is small you may have to do this in 2 batches. Cook until the pears are just barely beginning to soften, 5-7 minutes flipping once. Remove pears from the skillet to a plate until you are ready to assemble the naan.
Brush the top of each naan with a little of the oil mixture from the onions. Add 6-8 onion circles, 4 slices of Brie and 7-8 pear slices to each naan. Cook until the Brie has melted (60-90 seconds in the pizza oven, turning frequently; 6-8 minutes on the grill or in the oven. After closing the grill lid, turn the heat directly under the naan off, so that it doesn’t burn).
When the Brie has melted remove naan and finish each with a piece of prosciutto, 1/4 cup of arugula and a drizzle of honey.
Serve hot and enjoy!