Stuffed Pepper Casserole

Name: Stuffed Pepper Casserole
Prep time: 20 min
Cook time: 38 min
Total time: 58 min
Cuisine: American
Ingredients: 1 medium yellow onion; 1 medium green bell pepper; 1 medium red bell pepper; 3 tablespoons olive oil, divided; 1 pound lean ground beef; 1 1/4 teaspoons kosher salt, divided; 5 cloves garlic; 1/4 teaspoon red pepper flakes; 3 tablespoons tomato paste; 1/2 teaspoon dried oregano; 1 1/2 cups low-sodium chicken broth; 1 (14.5-ounce) can diced fire-roasted tomatoes; 2 teaspoons Worcestershire sauce; 1 cup long grain white rice, preferably jasmine; 1/4 teaspoon freshly ground black pepper; 2 ounces low-moisture mozzarella cheese, shredded (about 1/2 cup); 2 ounces sharp cheddar cheese, shredded (about 1/2 cup); 4 large sprigs fresh parsley