Balsamic Brown Sugared Mushrooms

by Katie of:
1 package whole button or cremini mushrooms
2 T. butter
2 T. olive oil
1 c. beef broth or stock
1/3 c. balsamic vinegar
1/3 c. brown sugar
1/2 t. salt
1/4 t. pepper
Optional but delicious:  pinch of red pepper flakes
Chop mushrooms in quarters.  Over medium heat in skillet, melt butter and add olive oil.  Swirl together to mix.  Add mushrooms and stirring frequently, let cook for 2 minutes.  Add remaining ingredients and bring to a simmer.  Simmer for 10 minutes or until sauce is syrupy like pancake syrup.  If sauce gets too thick, add a little more beef broth.  Add red pepper flakes, if using.  Spoon over grilled steaks.