Balsamic Mushrooms

1/4 c olive oil
12 oz white mushrooms, halved (quartered if large)
3 Tbsp balsamic vinegar
1 tsp coarse salt
1/4 tsp red pepper flakes
Freshly ground pepper

Heat oil in skillet over medium high heat. Add mushrooms, and cook until golden brown, about 5 min. Stir in vinegar, salt, pepper flakes, and season with pepper. Cook 1 min more. Transfer to a bowl and serve.