Heat oven: To 425 degrees F. Line your largest baking sheet with foil. Cook the mushrooms: Wipe out skillet and heat over medium-high. Add a drop of olive oil or a mix of olive oil and butter. Once it is very hot, add 1/3 to 1/2 of mushrooms, 1/3 to 1/2 of herbs and let sear in pan until brown underneath, about 2 to 3 minutes, before stirring and continuing to cook until tender and any liquid in the pan has cooked off, about 5 minutes. Season well with salt and pepper. Repeat with remaining mushrooms.