2In a large mixing bowl, combine ground beef, bread crumbs, diced onion, minced garlic, egg, and 1/4 cup milk. Mix gently with your hands until just combined; do not overwork.
3Stir in 2 tbsp of the ketchup, worcestershire sauce, salt, and pepper.
4Transfer mixture to a loaf pan and shape gently. Spread remaining ketchup over the top.
5Bake for 50–55 minutes, until internal temperature reaches 160°F.
6While meatloaf bakes, cut potatoes into quarters. Place in a large pot and cover with cold salted water. Bring to a boil and simmer for 15–18 minutes, until fork-tender. Drain in a colander.
7Return potatoes to pot. Add butter and 1/2 cup milk. Mash until creamy, seasoning with salt and pepper to taste.
8Let meatloaf rest 5 minutes before slicing. Serve with mashed potatoes.