Clean mushrooms and cut with a knife into similarly shaped thick pieces, if desired. Do not cut the mushrooms thin.

Add butter and olive oil to a pan. Heat over medium-high heat.

Once butter is melted and the mixture is hot, add mushrooms in small batches allowing room between mushrooms. Avoid crowding the pan. Allow mushrooms to cook, without stirring for 3-5 minutes.

Stir only occasionally allowing mushrooms to finish cooking completely for another few minutes. Add salt and pepper to taste. Cook time varies depending on the size of the mushroom. If the mushrooms give off a lot of liquid, keep cooking until the liquid has evaporated and the mushrooms are browned on both sides.

Serve warm over steak, in pasta, or as a side.