Preheat your oven to 350 degrees Fahrenheit (175 degrees Celsius). Prepare all the ingredients by gathering them in one place.

In a skillet over medium heat, melt the butter. Add the minced onion and garlic, cooking until the onion becomes soft and translucent, approximately 5 minutes. Once done, remove the skillet from heat and season with salt and pepper.

In a large mixing bowl, combine the onion and garlic mixture with the ground beef, crumbled bread, crushed crackers, beaten egg, sour cream, Worcestershire sauce, and half of the tomato sauce. Mix thoroughly until all ingredients are well incorporated. Gradually add milk, one teaspoon at a time, until the mixture reaches a moist yet firm consistency.

Transfer the mixture into a 5x9-inch loaf pan, shaping it to fit the pan.

Bake uncovered in the preheated oven for 40 minutes. Then, raise the oven temperature to 400 degrees Fahrenheit (200 degrees Celsius) and continue baking for an additional 15 minutes, ensuring the internal temperature reaches 160 degrees Fahrenheit (70 degrees Celsius).

In a small bowl, combine the remaining tomato sauce and ketchup. Pour this mixture over the meatloaf and bake for another 10 minutes.

Once completed, serve the meatloaf hot and enjoy the delightful flavors it offers!