Preheat your oven to 400°F (200°C) to achieve a golden-brown exterior on the meatballs.

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

Roll the meat mixture into 1-inch meatballs and place on a parchment-lined baking sheet. Bake for about 20 minutes until golden and the internal temperature reaches 165°F (74°C).

Heat 1 tablespoon of olive oil in a skillet over medium heat, and sauté sliced onion and minced garlic for about 3-4 minutes until translucent.

Pour in beef broth and a splash of Worcestershire sauce, bringing it to a simmer. Mix cornstarch with water to form a slurry and gradually add it to the skillet, cooking until thickened.

Peel and chop the Yukon Gold potatoes into quarters, cover with salted water, and add minced garlic. Boil for 15-18 minutes until tender.

Drain the potatoes and return to the pot. Add milk, butter, salt, pepper, and fresh parsley, mashing until creamy.

Serve the meatballs coated in gravy over the creamy mashed potatoes, drizzling any remaining gravy on top.