Step 1: Preheat your oven to 350°F (175°C). Line a baking sheet with foil or parchment paper for easy cleanup.
Step 2: In a large mixing bowl, gently combine the ground beef, breadcrumbs, milk, eggs, chopped onion, minced garlic, salt, pepper, 1/4 cup of the ketchup, mustard, 3/4 cup of the shredded cheddar cheese, and most of the crumbled bacon (saving about 2-3 tablespoons for the topping). Be careful not to overmix; just combine until all ingredients are incorporated.
Step 3: Transfer the meat mixture onto the prepared baking sheet and shape it into an even loaf, approximately 9x5 inches.
Step 4: Bake the meatloaf for 45 minutes.
Step 5: Remove the meatloaf from the oven. Spread the remaining 1/4 cup of ketchup evenly over the top, then sprinkle with the remaining 1/4 cup of shredded cheddar cheese and the reserved crumbled bacon.
Step 6: Return the meatloaf to the oven and continue baking for another 15-20 minutes, or until the internal temperature reaches 160°F (71°C) on a meat thermometer and the cheese is melted and bubbly.
Step 7: Once baked, remove the meatloaf from the oven and let it rest for 10-15 minutes before slicing. This allows the juices to redistribute, ensuring a more tender and flavorful result. Slice and serve hot!