Step 1

Melt the butter in a large non-stick pan over medium heat. Add the mushrooms, onions, salt, and pepper and cook them for 10 to 15 minutes or until the mushrooms have released their moisture. Add the garlic and cook it with the mushrooms and onions for a minute or so.

Step 2

Sprinkle the flour over the top of the mushrooms and stir to coat them. Add the white wine and stir. As it simmers, scrape up all of the browned bits off the bottom of the pan.

Step 3

Add the beef stock and mustard. Stir and then add the frozen meatballs. Cover the pan and adjust the heat to medium. Simmer the meatballs for ten minutes or until they are warmed through.

Step 4

Uncover the pan and take it off the heat. Add the sour cream and stir to combine. Serve the meatball stroganoff with noodles or rice. Garnish with chopped parsley or chives.