In a large bowl, combine ground beef, ground pork, breadcrumbs, milk, egg, salt, pepper, nutmeg, and allspice. Mix until well combined.
Shape mixture into 1-inch meatballs.
Heat butter and olive oil in a large skillet over medium heat. Cook meatballs in batches until browned on all sides and cooked through. Remove meatballs and set aside.
Prepare Sauce:
In the same skillet, melt butter. Whisk in flour to make a roux and cook for 1-2 minutes.
Gradually add beef broth while whisking to prevent lumps. Simmer for 2-3 minutes.
Stir in heavy cream, Worcestershire sauce, salt, and pepper. Simmer until sauce thickens.
Return meatballs to the skillet, coat with sauce, and heat through.
Serve hot with mashed potatoes, noodles, or rice.
Notes
Variation: Use all beef or all pork if preferred.
Make Ahead: Meatballs can be cooked and refrigerated for 1 day before adding sauce.
Serving Suggestion: Serve over egg noodles or mashed potatoes for a classic Swedish meal.
Storage: Store in an airtight container in the fridge up to 2 days. Reheat gently.