Using a paring knife, gently cut 3/4 of the way around the top of each pepper, leaving a hinge. Carefully remove the seeds, and drain the liquid from the peppers. Cut core seeds from the top of each pepper. You will be left with 6 seed-free whole hollow peppers with attached lids.
Insert 1 piece of mozzarella into each pepper. Follow with a small sprig of rosemary, salt, pepper, and 1/2 teaspoon olive oil. Close the top of each pepper with attached lid.
Heat grill to medium-high. Place peppers on grill, and cook, using tongs to rotate, until the cheese has melted, about 2 minutes per side. Remove from heat, and transfer to serving platter. Drizzle with olive oil, sprinkle with salt and pepper, and garnish with a sprig of rosemary. Serve immediately.
2 red peppers
2 yellow peppers
2 orange peppers
Turn over 3 burner grates on a gas range so that they are concave. Set range to a high flame, and place 2 peppers on each grate, so that they are directly in the flame. Roast peppers, turning occasionally with tongs, until they are evenly charred and soft all over. Do not worry if peppers split.
Transfer each pepper to a paper towel, and wrap tightly. Let them steam for at least 5 minutes. (This "sweats" the peppers, loosening the skin.) Remove the charred skin with the paper towel, rubbing gently, if necessary. It is not recommended that you rinse the peppers under running water to remove the skin; this will wash away a lot of the flavor.
Yield: 4 servings