01 - In a large bowl, combine breadcrumbs and milk. Allow to soak for 5 minutes until the milk is absorbed.
02 - Add ground beef, ground pork, finely chopped onion, minced garlic, egg, salt, pepper, allspice, and nutmeg to the soaked breadcrumbs. Mix just until the ingredients are combined without overworking the mixture.
03 - Roll the mixture into small, walnut-sized balls, approximately 1 1/4 inches in diameter. Arrange formed meatballs on a tray.
04 - Heat butter and vegetable oil in a large skillet over medium heat. Cook the meatballs in batches, turning occasionally, until browned on all sides, about 8 minutes. Remove meatballs from the skillet and set aside.
05 - Melt butter in the same skillet over medium heat. Whisk in flour and cook for 1 minute, stirring constantly.
06 - Gradually pour in beef or vegetable stock while whisking to prevent lumps. Stir in heavy cream, soy sauce, and Dijon mustard. Season with salt and black pepper. Simmer for 5 to 7 minutes, stirring, until sauce thickens.
07 - Return browned meatballs to the skillet, coating them fully in the sauce. Simmer gently for 5 to 10 minutes until warmed through.
08 - Serve meatballs hot with cream sauce, accompanied by mashed potatoes, lingonberry jam, and steamed vegetables if desired.