Make the onion gravy:
In the same skillet, add butter and olive oil. Once the butter is melted, add the sliced onions and cook, stirring occasionally, until the onions are softened and golden brown (about 10-15 minutes).
Sprinkle the flour over the onions and stir to combine. Cook for another 2 minutes to make a roux (a thick paste).
Gradually add the beef broth while stirring to avoid lumps. Add Worcestershire sauce and thyme, then bring the mixture to a simmer.
Season with salt and pepper to taste. Let the gravy simmer for about 5 minutes until it thickens.
Combine the meatballs and gravy:
Return the meatballs to the skillet with the onion gravy. Stir gently to coat the meatballs with the gravy.
Cover and simmer for another 10-15 minutes, allowing the meatballs to cook through and absorb the flavor of the gravy.
Serve:
Serve the meatballs in onion gravy over mashed potatoes, rice, or with crusty bread for a complete meal.
Enjoy your comforting and flavorful meatballs in onion gravy!
