Step 1

Whisk the egg yolk in a medium-sized bowl until lightly mixed. Add the onions, parsley, breadcrumbs, salt, pepper, nutmeg, and allspice and stir to combine.

Step 2

Add the ground pork and ground beef to the egg mixture. Use your hands or a large spoon to thoroughly mix the egg mixture into the ground meat mixture.

Step 3

Scoop the meatballs into 2-inch portions and use the palms of your hands to roll them into smooth balls. Set aside.

Step 4

Heat oil in a 10-inch skillet or sauté pan over medium heat. Add the meatballs to the pan and cook, turning them every 2 minutes until browned on all sides, about 8 minutes total. Transfer the meatballs to a plate.

Step 5

Melt butter in the same skillet. Add flour and stir to form a paste; cook, stirring frequently for 30 seconds.

Step 6

Add beef broth and whisk until smooth; bring to a simmer. Return meatballs to the pan and simmer in the gravy, uncovered, until the meatballs are cooked through and the gravy has thickened, about 5-7 minutes.

Step 7

Remove from heat and stir in sour cream. Taste the gravy and add additional salt, if needed. Enjoy the meatballs and gravy as-is or serve with pasta or mashed potatoes.