Preheat your oven to 400°F (200°C).

In a large mixing bowl, combine ground beef, breadcrumbs, milk, minced garlic, chopped onion, Worcestershire sauce, egg, salt, and black pepper. Mix until well blended.

Shape the mixture into meatballs, aiming for a diameter of about 1-1.5 inches.

Heat olive oil in a large oven-safe skillet over medium heat. Brown the meatballs on all sides in batches, then remove and set aside.

In the same skillet, melt the butter over medium heat for the gravy. Stir in flour and cook until golden brown.

Gradually whisk in the beef broth, then add ketchup and Dijon mustard, bringing to a simmer.

Return meatballs to the skillet and spoon gravy over them. Transfer the skillet to the preheated oven and bake for 15-20 minutes until cooked through.

Bring a large pot of salted water to a boil and add cubed potatoes. Cook until tender, then drain and return to pot.

In a small saucepan, combine butter, milk, and minced garlic. Heat gently until butter melts.

Pour the butter mixture over the drained potatoes and mash until smooth. Stir in chopped parsley, seasoning with salt and pepper to taste.

Plate the garlic herb mashed potatoes, nestle the meatballs atop, and drizzle generously with gravy. Garnish with fresh parsley and serve with steamed vegetables or crusty bread.