1-First Step: Sauté Aromatics Heat 1 tablespoon of olive oil in a large, high-sided skillet over medium heat. Add the finely diced yellow onions and minced garlic, cooking for about 5 minutes until softened and fragrant but not browned. Remove from heat and let the mixture cool completely before adding to the meat to avoid overcooking the egg and breadcrumbs.

2-Second Step: Combine Meatball Mixture In a large bowl, combine the panko breadcrumbs, Parmesan cheese (if using), whisked egg, milk, cooled onion and garlic mixture, salt, oregano, allspice, nutmeg, black pepper, and parsley. Mix gently to combine. Fold in the ground beef and ground pork carefully, ensuring the mix is uniform but not overworked, which can make meatballs tough.

3-Third Step: Shape and Chill Shape the meat mixture into approximately 1½-inch meatballs aim for about 33 small meatballs or fewer larger ones. For best results, chill the formed meatballs in the refrigerator for at least 15 minutes or up to overnight, which helps them hold their shape during cooking.

4-Fourth Step: Brown Meatballs Heat the remaining 1 tablespoon of olive oil (plus optionally 1 tablespoon of butter) in the skillet over medium-high heat. Brown the meatballs in batches, cooking about 1 minute per side until golden but not fully cooked through. Remove and set aside on a plate lined with paper towels to absorb excess fat.

5-Fifth Step: Make the Sauce In the same skillet, melt 4 tablespoons of butter over medium heat. Stir in the flour and cook for 2 to 3 minutes while stirring continuously until the mixture turns a light golden color (roux). Gradually whisk in the beef broth mixed with bouillon cube, Worcestershire sauce, Dijon mustard, and dried parsley. Bring the sauce to a boil, then reduce heat and simmer until it thickens.

6-Sixth Step: Finish the Sauce and Simmer Meatballs Place the sour cream in a separate bowl. Temper it by adding about ¼ cup of the hot sauce and stirring until smooth, then slowly mix it back into the skillet to avoid curdling. Return the browned meatballs and any juices to the skillet. Spoon sauce over meatballs, cover partially, and simmer on low heat for 10 to 15 minutes until meatballs are cooked through.

7-Final Step: Taste and Serve Adjust seasoning with salt and pepper as needed. Garnish with fresh parsley for color and serve hot over egg noodles, mashed potatoes, or your preferred side dishes to enjoy the classic Swedish meatballs experience.