Heat olive oil in a large skillet over medium heat. Add onion and cook until translucent, about 5 minutes. Stir in garlic, carrots, and bell peppers, sauté for another 8-10 minutes.

Push the sautéed vegetables to the side and add ground beef, cooking for 5-7 minutes until browned. Drain excess fat.

Combine the sautéed ingredients and beef, then add tomato sauce, diced tomatoes, and beef broth. Sprinkle in Italian seasoning, salt, and pepper. Simmer for 10 minutes.

Preheat the oven to 375°F (190°C). Transfer mixture to a casserole dish, top with breadcrumbs and cheese.

Bake in the preheated oven for 25-30 minutes until cheese is golden and bubbly. Allow to cool for 5-10 minutes before serving.