Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.

In a large mixing bowl, combine ground beef, breadcrumbs, milk, chopped onion, minced garlic, egg, Worcestershire sauce, salt, and the dried spices.

Shape the mixture into 1.5-inch meatballs and place them on the prepared baking sheet.

Bake the meatballs for approximately 20 minutes until cooked through.

Boil chopped potatoes until fork-tender, then mash with garlic, butter, milk, and parsley.

In a saucepan, cook flour until golden, then slowly whisk in beef broth, soy sauce, and Dijon mustard.

Carefully transfer the baked meatballs into the gravy, toss to coat and simmer briefly.

Serve meatballs over the mashed potatoes and drizzle with additional gravy.