Beef Muffin Cups

This is a favorite or ours. When we make it we use our left over pot roast instead of a sirloin like it original calls for. I also use 1 large onion instead of 3 medium.

3 medium onions, thinly sliced
1/4 cup butter, cubed
1 boneless beef top sirloin steak (1-inch thick and 6 ounces), cut into 1/8-inch slices
1 teaspoon all-purpose flour
1 teaspoon brown sugar
1/4 teaspoon salt
1/2 cup beef broth
1 tube (16.3 ounces) large refrigerated flaky biscuits
3/4 cup shredded part-skim mozzarella cheese
1/3 cup grated Parmesan cheese, divided

In a large skillet, cook onions in butter over medium heat for 10-12 minutes or until very tender. Remove and keep warm. In the same skillet, cook steak for 2-3 minutes or until no longer pink. Return onions to pan. Stir in the flour, brown sugar and salt until blended; gradually add broth. Bring to a boil; cook and stir for 4-6 minutes or until thickened.
Separate biscuits; split each horizontally into three portions. Press onto the bottom and up the sides of eight ungreased muffin cups, overlapping the sides and tops. Fill each with about 2 tablespoons beef mixture.
Combine mozzarella cheese and 1/4 cup Parmesan cheese; sprinkle over filling. Fold dough over completely to enclose filling. Sprinkle with remaining Parmesan cheese.
Bake at 375° for 12-15 minutes or until golden brown. Let stand for 2 minutes before removing from pan. Serve warm. Yield: 4 servings.