Best Meatloaf

Name: Best Meatloaf
Prep time: 15 min
Cook time: 1 h 10 min
Total time: 1 h 25 min
Cuisine: American
Ingredients: 1 tablespoon butter; 0.25 cup minced onion; 2 cloves garlic, minced; 1.5 teaspoons salt; 1.5 teaspoons freshly ground black pepper; 2 pounds extra-lean ground beef; 3 slices bread, toasted and crumbled; 7 buttery round crackers, crushed; 1 egg, lightly beaten; 3.5 tablespoons sour cream; 1.5 tablespoons Worcestershire sauce; 1 (15 ounce) can tomato sauce, divided; 0.25 cup milk, or as needed; 3 tablespoons ketchup