Modified from Simple & Delicious
2 medium onions, diced [the recipe called for 3, but that was too many for the amount of meat in the recipe we thought]
1/4 cup butter
1 boneless beef top sirloin steak (1 inch thick, 6 oz), cut into thin slices [I just bought whatever steak was on sale]
1 tsp flour
1 tsp brown sugar
1/4 tsp salt
1/2 cup beef broth
1 tube (16.3 oz) large refrigerated flaky biscuits [these are 8 packs and make sure they are actually the large and match this weight as you will need to pull them apart]
3/4 cup mozzarella cheese, grated
1/3 cup Parmesan cheese, grated, divided [Because of what you are using it for, actually buy Parmesan, not the dried stuff in a can you use on spaghetti...I just buy pre-shredded in the grocery brand - it is no more expensive than pre-shredded cheddar if you do that.]
In a large skillet, cook onions in butter over medium heat until very tender. Remove and keep warm. In the same skillet, cook steak until tender. Add onions back in and stir in flour, brown sugar and salt until blended [i.e., you are cooking the flour a bit so you don't actually taste it - learned that from Rachael Ray]. Gradually add broth in. Bring to a boil; cook and stir for 4-6 minutes or until thickened.
Separate biscuits; split each one horizontally into three pieces and then press into the bottom and up the sides of ungreased muffin cups, overlapping the sides and tops. [Note: this is a bit of a pain, but you will get this to work and then try to stretch it a bit so you can wrap it over the top a little at the end.] Fill each with about 2 tablespoons beef mixture.
Combine mozzarella and 1/4 cup of Parmesan cheese; sprinkle over filling. Fold dough over completely to cover filling. Sprinkle tops with remaining Parmesan.
Bake at 375 for 12-15 minutes or until golden brown. Let stand for a few minutes before serving from pan. Serve warm.
Makes 4 servings (it makes 24 little "cups," but each are really small, it takes like 4 to make a meal).