Preheat the oven to 350°F.
In a large skillet over medium heat, cook the ground beef, onion, and garlic until the beef is browned and the onion is tender, about 5-7 minutes. Drain any excess fat.
Stir in the diced tomatoes, tomato sauce, oregano, basil, salt, and pepper. Bring to a simmer and cook for 5 minutes.
Add the cooked macaroni, mixed vegetables, milk, and half of the cheddar cheese to the skillet. Mix well until everything is combined.
Transfer the mixture to a greased 9x13-inch baking dish. Sprinkle the remaining cheddar cheese on top, followed by the breadcrumbs.
Bake in the preheated oven for 25-30 minutes, or until the casserole is bubbly and the top is golden brown.