In a large mixing bowl, thoroughly combine the ground beef and ground pork (if using). Add the finely chopped onion, minced garlic, breadcrumbs, egg, milk, ground allspice, ground nutmeg, salt, and pepper. Mix gently until all ingredients are just incorporated.
Using your hands, form the mixture into small meatballs, each about 1 inch in diameter, and place them on a baking sheet or plate.
In a large skillet, heat the olive oil over medium heat. Add the meatballs in batches, searing them for about 5-7 minutes until browned on all sides. Transfer the cooked meatballs to a plate.
In the same skillet, add the beef broth, soy sauce, and lingonberry jam. Stir to combine and bring to a gentle simmer.
Gradually whisk in the heavy cream, cooking and stirring occasionally until the sauce thickens slightly, about 5 minutes.
Add the cornstarch slurry to the simmering sauce and cook for an additional minute, stirring continuously until creamy and smooth. Adjust seasoning with salt and pepper.
Return the browned meatballs to the skillet, gently stirring to coat them in the creamy sauce. Let them simmer together for 2-3 minutes.
Notes
For an appealing presentation, garnish with parsley and serve with mashed potatoes.
Keyword lingonberry sauce, meatballs, Swedish cuisine