First thing, prep your onions, mushrooms and garlic. Set aside. To split chicken breasts: lay breast flat on clean cutting board, find the halfway point between top and bottom. Using a very sharp knife, carefully cut horizontally through the breast as if you would a butterfly cut. Instead of stopping when you reach the other side, finish cutting all the way through to completely split top and bottom. Repeat with remaining breasts so you have 6 thin breast pieces.

Season both sides of breast pieces with desired amounts of salt, pepper, garlic and onion powders. Heat a large, deep sided saute pan over medium heat. When hot (a drop of water "sizzles") add 2 tbs olive oil and swirl to coat.

Add chicken breasts to hot pan, arranged so they will all fit flat but not overlapping. Cook On the first side, untouched, for 5 minutes to get a nice, browned sear. When first side is done breasts will "release" from the pan easily.

Flip each breast to sear second side and finish cooking, about 5 minutes more, again untouched for best sear. Remove to plate, tent with foil to keep warm and set aside.

Add onion to hot pan and cook until translucent, about 2 minutes. Add sliced mushrooms, sprinkle minced garlic, thyme and a pinch of s&p on top, then drizzle with remaining 1tbs olive oil. Stir to combine everything.

Cook until mushrooms begin to exude their juices and shrink down, stirring frequently and scraping up brown bits that have been stuck to pan. About 5 - 7 minutes more.

Add beef broth. Increase heat to medium high to bring to a boil until broth has reduced slightly (not quite by half) about 5 - 7 minutes again. No need to stir more than a couple times here.

Reduce heat to medium low. Add balsamic vinegar and heavy cream. Stir to incorporate fully. Simmer some more until sauce begins to thicken. Again, this took about 5 minutes for me.

Stir in freshly grated cheese until melted into sauce, this will also help thicken some more. Return chicken breasts to pan, turn to coat in sauce. Turn heat to low, cover and let sit 5 minutes to warm chicken through.

Serve with sauce drizzled on top and a crisp side salad for a lower carb option, or any other desired sides. Enjoy!