Trim the stem ends of the mushrooms. Cut the mushrooms in equally sized pieces for uniform cooking.

Heat a heavy-bottomed pan to high heat. Add a small amount of oil to the pan.

Next, add butter. Adding the oil first will prevent the butter from browning.

Once the butter is melted, add the mushrooms in an even layer. Don't overcrowd the pan.

Turn the pan heat down to medium and cook the mushrooms on one side. Season the mushrooms liberally.

Turn each mushroom over individually.

The mushrooms will all be well cooked on the outside, but not burnt.

Once they are cooked, turn the mushrooms out onto a parchment lined baking sheet. Spread them in an even layer to prevent carry-over cooking.

Carefully wipe the pan out with a clean towel, and start from the beginning with a second batch. Turn on high heat, oil, butter, mushrooms, medium heat, season and so on.