2) Place the jalapenos on a sheet tray and roast for 10 minutes. Remove from the oven and leave to cool.
3) Heat the oil in a medium saute pan. Add the sausage and cook for 5 to 7 minutes. Add the onions, peppers, and garlic and cook to soften for about 5 minutes.
4) Remove and place in a large bowl. Cool to room temperature, then add the mascarpone and Parmesan. Mix the ingredients thoroughly and season with salt and pepper.
5) Place approximately 1 tbsp of mixture into each jalapeno half, and top with 1/2 tsp of mozzarella cheese.
6) Turn the grill to medium. Place the sheet tray of stuffed peppers under the grill until the mozzarella cheese melts.