- Meatballs:
- 1 pound lean ground beef
- 1/2 pound ground pork
- 1/4 cup diced onion
- 1/4 cup Italian bread crumbs
- 1 egg
- 1 tablespoon Worcestershire sauce
- 2 pinches ground cinnamon
- 2 pinches ground nutmeg
- 2 pinches dried parsley
- salt and ground black pepper to taste
- 2 tablespoons vegetable oil
- Gravy:
- 1 1/2 teaspoons cornstarch
- 1 (14 ounce) can beef broth
- 1/4 cup sour cream
- 1 (4.5 ounce) can sliced mushrooms, drained
- Mix ground beef, ground pork, onion, bread crumbs, egg, Worcestershire sauce, cinnamon, nutmeg, parsley, salt, and pepper in a large bowl until evenly mixed; shape into 12 2-inch balls.
- Heat vegetable oil in a large skillet over medium-high heat. Cook meatballs in hot oil until browned on all sides and somewhat firm, 5 to 7 minutes. Remove browned meatballs with a slotted spoon to a slow cooker.
- Stir cornstarch into drippings remaining in the skillet; add beef broth. Bring the broth mixture to a simmer, reduce heat to medium-low, and simmer until thickened, about 2 minutes. Stir sour cream into the broth mixture until smooth. Add mushrooms and stir. Season the sauce with salt and pepper; pour over meatballs in the slow cooker.
- Cook in slow cooker on High for 4 hours.