In a small bowl, mix the breadcrumbs and milk. Let them soak for 5 minutes.
In a larger bowl, combine the ground meat, soaked breadcrumbs, egg, onion, allspice, nutmeg, salt, and pepper. Mix everything thoroughly until well combined.
Using your hands, shape the mixture into small balls, about 1 inch (2.5 cm) in diameter. Aim for uniform size to ensure even cooking.
In a large skillet, melt the butter over medium heat. Fry the meatballs in batches, turning frequently to brown on all sides. This should take about 8-10 minutes. Transfer the meatballs to a plate and keep warm.
In the same skillet, melt the butter over medium heat. Stir in the flour and cook for 1-2 minutes until lightly browned. Gradually whisk in the beef broth, ensuring no lumps form. Add the heavy cream, soy sauce, and Dijon mustard. Simmer the gravy until it thickens, about 3-5 minutes.
Return the meatballs to the skillet, coat them with the gravy, and let them simmer for 5 minutes to heat through. Serve hot with mashed potatoes, lingonberry sauce, or cooked vegetables.
