Over medium-high heat, saute onions and garlic until fragrant.
Add red bell pepper, tomatoes and Italian seasoning, sweating the vegetables until liquid evaporates, about 5 minutes. Set aside.
In a separate pan over medium-high heat, start the sauce by sauteing garlic until fragrant then add in tomato sauce. Crumble in the beef bouillon cube and mix well.
Season the sauce with Italian seasoning, red pepper flakes, Worcestershire sauce, sugar and salt and pepper to taste. Simmer for 5 minutes.
Combine ground beef, eggs, Italian breadcrumbs, Parmesan cheese, 1 cup mozzarella cheese, ½ cup marinara sauce, cooked vegetables, Worcestershire sauce and salt and pepper. Form into a loaf using your hands, mixing all the ingredients thoroughly.
Coat the top of the loaf with the remaining marinara sauce and spread evenly using the back of a spoon. Finish by topping with the remaining 1 cup of mozzarella cheese.
Bake uncovered on a baking sheet at 350°F for 45 minutes or until a meat thermometer reads 160°F in the middle of the meatloaf. Let it stand for 10 minutes before cutting.
Dish and serve hot.
