1. Preheat oven to 425 degrees.
2. Brush pepper skins with 1 tablespoon olive oil and season with salt.
3. Place skin side down on large baking sheet.
4. Roast for about 20 minutes until peppers are tender and skins are lightly charred.
5. Remove from oven and set aside.
6. Reduce oven temperature to 350.
7. Meanwhile heat remaining olive oil in a large skillet over medium heat.
8. Add onions and cook until just tender, about 8-9 minutes.
9. Add garlic and cook for about a minute longer until fragrant.
10. Add Italian sausage and rosemary and cook, breaking up the chunks until sausage is cooked and crumbly, about 10 minutes.
11. Increase heat to high and add 1 1/2 tablespoons balsamic vinegar. Cook on high for 1-2 minutes until bubbly and balsamic absorbs into sausage mixture.
12. Lightly spray a 9×13 baking dish with cooking spray.
13. Add sausage mixture into pepper halves and place in baking dish.
14. Sprinkle each pepper with mozzarella and Parmesan cheese.
15. Bake at 350 degrees for about 20 minutes until cheese is melted.
16. Remove from oven. Garnish with additional chopped rosemary, basil and drizzle with balsamic glaze (see below).
17. Serve immediately.

Balsamic Glaze

1. Pour balsamic vinegar in a small saucepan.
2. Cook on medium low heat for about 10 minutes until liquid reduces by half.
3. Remove from heat and set aside until ready to serve.