Preheat oven : to 375°F (190°C). Grease a loaf pan or line a baking sheet with foil.
Prepare meat mixture : In a large bowl, combine ground beef, breadcrumbs, eggs, milk, onion, garlic, Worcestershire sauce, salt, pepper, parsley, and paprika. Mix gently until just combined.
Shape loaf : Transfer mixture into a loaf pan or form a free-standing loaf on the baking sheet.
Make the glaze : In a small bowl, whisk ketchup, brown sugar, vinegar, and mustard.
Glaze and bake : Spread half of the glaze over the top of the loaf. Bake for 45 minutes.
Add second glaze layer : Remove loaf, spread with remaining glaze, and return to oven. Bake for another 10–15 minutes, or until internal temperature reaches 160°F (71°C).
Rest u0026 slice : Let the meatloaf rest 10 minutes before slicing to keep it moist.