Peperonata:
- 3 red bell peppers, cut into strips
- 1 1/2 tablespoons extra-virgin olive oil, divided
- 1 1/2 tablespoons drained capers
- 1 teaspoon red-wine vinegar
- 1/8 teaspoon hot red pepper flakes
Meatballs:
- 3 slices Italian bread, torn into pieces (1 cup)
- 1/3 cup milk
- 3 ounces sliced pancetta, finely chopped
- 1 small onion, finely chopped
- 1 small garlic clove, minced
- 2 tablespoons extra-virgin olive oil, divided
- 1 large egg
- 1 pound ground chicken
- 3 tablespoons finely chopped flat-leaf parsley
- 1 tablespoon tomato paste
Make peperonata:
Preheat oven to 400°F with racks in upper and lower thirds.
Toss bell peppers with 1 tablespoon oil, then roast in a 4-sided sheet pan in lower third of oven, stirring occasionally, until tender and browned, about 35 minutes.
Stir together capers, vinegar, red pepper flakes, and remaining 1/2 tablespoon oil in a medium bowl and set aside.
Make meatballs while peppers roast:
Soak bread in milk in a small bowl until softened, about 4 minutes.
Cook pancetta, onion, and garlic in 1 tablespoon oil with 1/2 teaspoon each of salt and pepper in a 10-inch skillet over medium heat until onion is softened, about 6 minutes. Cool slightly.
Squeeze bread to remove excess milk, then discard milk. Lightly beat egg in a large bowl, then combine with chicken, pancetta mixture, bread, and parsley. Form 12 meatballs and arrange in another 4-sided sheet pan.
Stir together tomato paste and remaining tablespoon oil and brush over meatballs, then bake in upper third of oven until meatballs are just cooked through, 15 to 20 minutes.
Toss bell peppers with caper mixture. Serve meatballs with peperonata.
