Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.
In a mixing bowl, combine the ground beef, ground pork, bread crumbs, milk, egg, chopped onion, salt, black pepper, allspice, nutmeg, and parsley. Use your hands to mix everything until just combined.
Shape the mixture into meatballs, about 1 inch in diameter, and place them on the prepared baking sheet.
Bake the meatballs for 20 minutes in the preheated oven until they are cooked through and browned.
Meanwhile, prepare the gravy. In a skillet, melt the butter over medium heat. Add the flour and whisk for about 2 minutes until golden brown to make a roux.
Slowly add the beef broth while whisking constantly to avoid lumps. Continue to whisk until the sauce thickens, about 5 minutes.
Stir in the heavy cream and season with salt and pepper to taste. Let it simmer for a few minutes until well combined.
Once the meatballs are done baking, add them to the gravy and let them simmer together for about 5 minutes to absorb the flavors.
Serve the Swedish meatballs with mashed potatoes, lingonberry sauce, or over egg noodles as desired.