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

In a large mixing bowl, combine ground beef, breadcrumbs, milk, onion, and garlic. Add egg, Worcestershire sauce, salt, pepper, parsley, onion powder, and garlic powder. Mix well.

Shape the mixture into 1.5-inch meatballs and place them on a prepared baking sheet. Bake for about 20 minutes until browned and cooked through.

In a saucepan, bring water to boil, add potatoes and cook for 15-20 minutes until tender.

Drain the potatoes, return them to the saucepan, add garlic, butter, and milk. Mash until smooth, stir in parsley, salt, and pepper.

In a frying pan, heat flour until light golden, then whisk in beef broth. Add soy sauce and Dijon mustard, simmer until thickened.

Add cooked meatballs to the gravy, gently toss to coat, and heat through.

Serve meatballs over mashed potatoes, drizzle with gravy, and garnish with fresh parsley.