Preheat oven to 375°F (190°C).

In a large mixing bowl, combine ground beef, breadcrumbs, milk, eggs, onion, garlic, ketchup, Worcestershire sauce, salt, and pepper. Mix until just combined.

Shape the mixture into a loaf and place it in a greased baking dish or loaf pan.

Spread an additional layer of ketchup on top of the loaf for a glaze.

Bake for 55–60 minutes, or until internal temperature reaches 160°F (71°C). Let rest for 10 minutes before slicing.

Meanwhile, place peeled and cubed potatoes in a large pot and cover with cold water. Add salt.

Bring to a boil and cook until potatoes are fork-tender, about 15–20 minutes.

Drain potatoes and return to pot. Add butter, milk, salt, and pepper. Mash until smooth and creamy.

Serve slices of meatloaf with mashed potatoes on the side, garnished with fresh parsley if desired.