Preheat the oven to 350 degrees F and lightly grease a loaf pan.
In a large mixing bowl, combine the ground beef, diced bell pepper, chopped basil, diced onion, breadcrumbs, egg, milk, salt, and black pepper.
Mix the ingredients with your hands until just combined, taking care not to overwork the meat.
Transfer the mixture to the prepared loaf pan and shape it into an even loaf.
Spread the ketchup evenly over the top of the meatloaf.
Bake for 55 to 60 minutes, or until the internal temperature reaches 160 degrees F.
Let the meatloaf rest for 10 minutes before slicing and serving.