Caramelize mushrooms: Melt 2 tablespoons butter with 1 tablespoon olive oil over medium heat. Increase temperature to medium-high and add half of the mushrooms. Give them a stir to evenly coat in the butter then arrange mushrooms in a single layer. Cook mushrooms for 3 minutes per side or until golden. Once evenly browned, season mushrooms lightly with freshly cracked salt and pepper and give them a stir. Remove mushrooms from skillet and repeat with remaining mushrooms; transfer all mushrooms to a plate.