Prepare the Breadcrumb Mixture: In a large bowl, mix the panko breadcrumbs, milk, and heavy cream. Let the mixture soak for 5 minutes to allow the breadcrumbs to absorb the liquid.

Mix the Meatball Ingredients: Add the egg, finely chopped garlic, salt, black pepper, white pepper powder, and all-purpose seasoning to the breadcrumb mixture. Stir until well combined. Incorporate the cooked onions, ground beef, and parsley. Mix gently until the ingredients are just combined, being careful not to overmix to keep the meatballs tender.

Shape the Meatballs: Using your hands or a small scoop, shape the mixture into evenly sized meatballs (about 1½ inches in diameter). Place them on a plate or tray.

Cook the Meatballs : Heat the butter and vegetable oil in a large skillet over medium heat. Add the meatballs in batches, ensuring they have enough space to cook evenly. Cook the meatballs for 6-8 minutes, turning occasionally, until they are browned on all sides and cooked through. Remove from the skillet and set aside.

Optional Gravy: If desired, make a classic Swedish gravy by whisking 2 tablespoons of flour into the pan drippings, then gradually adding 2 cups of beef broth and ½ cup of heavy cream. Simmer until thickened, and season with salt and pepper.

Serve: Serve the Swedish meatballs warm with gravy, mashed potatoes, or egg noodles. Garnish with additional parsley if desired.