Step 1

In a large skillet, heat a tablespoon of butter over medium heat. Add the onions and allow them to soften and become translucent about 3-5 minutes. Remove to a medium bowl and allow them to cool.

Step 2

In a small bowl, pour the milk over the bread and press down with a spoon or your fingers so that the bread soaks up all the milk, let sit 5 minutes.

Step 3

When the onions have cooled, add the ground beef, bread mixture, an egg, salt, pepper, nutmeg, and allspice to the bowl and mix until just combined. Don't overmix the meat as it will result in tough meatballs. Shape into 18-22 meatballs that are about 1- 1 ¼ inch in diameter.

Step 4

Heat 1 tablespoon of butter along with oil in a skillet over medium-high heat. Add the meatballs and cook for 6-9 minutes, turn every couple of minutes to ensure even browning. Remove to a plate. If you don't have a skillet large enough to hold all the meatballs, do it in batches, do not overcrowd the pan, you don't want them to steam as they won't develop that brown outer crust and as a result, the sauce will be very light in color.

Step 5

Add the remaining 3 tbsp of butter to the skillet on medium-low heat. Sprinkle the flour in and whisk for 1-2 minutes or until it turns golden brown. Slowly pour the beef broth in while you whisk. Lower the heat, whisk in the sour cream until it dissolves completely.

Step 6

Add the garlic powder, a ½ teaspoon of mustard, and Worcestershire sauce and let come to a gentle simmer before lowering the heat. Allow sauce to thicken for 6-10 minutes or until it reaches desired consistency. Taste and adjust with additional mustard as desired. Add meatballs in when there are 4 minutes remaining. Keep in mind the sauce will thicken as it sits, so if you aren't serving right away, consider leaving it a little thinner. Serve on top of buttered egg noodles or mashed potatoes. Top with fresh parsley if desired!