Step 1: Prepare the Meatball Mixture : In a small bowl, soak breadcrumbs in milk for 5 minutes. In a large bowl, combine ground beef, soaked breadcrumbs, grated onion, egg, salt, pepper, nutmeg, and allspice. Mix gently until just combined (do not overmix to keep meatballs tender).
Step 2: Form and Brown the Meatballs : Roll mixture into 1-inch meatballs and set aside on a plate. In a large skillet, heat butter or oil over medium heat. Add meatballs in batches, cooking until browned on all sides (about 5–6 minutes). Remove meatballs and set aside.
Step 3: Make the Cream Sauce : In the same skillet, melt 2 tbsp butter over medium heat. Whisk in flour to create a roux, cooking for 1–2 minutes until lightly golden. Gradually whisk in beef broth and bring to a simmer. Stir in heavy cream and Worcestershire sauce, simmering for 3–5 minutes until sauce thickens. Season with salt and pepper to taste.
Step 4: Combine Meatballs and Sauce : Return browned meatballs to the skillet with the cream sauce. Simmer for an additional 5–7 minutes, allowing meatballs to finish cooking and absorb the sauce.