Baked Sweet-and-Sour Chicken

INGREDIENTS

• 3 tablespoons ketchup
• 1 1-inch piece ginger, peeled and finely grated
• Kosher salt
• 3 teaspoons extra-virgin olive oil
• 1 bunch scallions, cut into 3-inch pieces
• 2 tablespoons orange marmalade or apricot preserves
• 2 teaspoons low-sodium soy sauce
• 8 skin-on, bone-in chicken thighs (3 to 3 3/4 pounds)
• 2 bell peppers (1 red, 1 yellow), quartered lengthwise
• 2 teaspoons balsamic vinegar
• Large pinch of cayenne pepper (optional)
• Cooked white rice, for serving (optional)