Preheat your oven to 350°F (176°C).
In a small bowl, combine the ketchup, brown sugar, and mustard.
Set the mixture aside for later use.
In a large mixing bowl, combine the ground beef, onion, bell pepper, eggs, cheese, milk, Ritz crackers, salt, pepper, and garlic powder.
Mix the ingredients thoroughly using your hands until they are well combined.
Shape the mixture into a loaf.
Place the loaf in an ungreased 13x9-inch baking dish.
Bake the meatloaf in the preheated oven for 30 minutes.
Remove the meatloaf from the oven and spread the ketchup mixture evenly over the top.
Return the meatloaf to the oven and bake for an additional 20-30 minutes, or until fully cooked through and nicely browned on top.
Let the meatloaf rest for about 10 minutes before slicing and serving.