Sear chicken in a pan until brown on both sides, remove from pan and cook through in a 350 degree oven.
In the same pan at a medium–high heat add ¼ cup of chopped pancetta and a handful of roughly chopped mushrooms and lightly toss.
Deglaze pan with 1 cup of chicken stock and lightly toss.
Reduce heat to a medium low and add salt and pepper.
Let simmer for 3 minutes to let the liquid reduce and thicken.
Add a generous nub of butter and stir until melted.
Place your chicken on a plate, and pour the sauce right on top, making sure to get a nice helping of mushrooms and pancetta.