How to Make a Mushroom Pan Sauce for Steak
First, cook a steak in a heavy-bottomed pan (preferably cast iron) on the stove. Remove the meat and place the still-hot pan over moderate heat.
Add a medium-sized sliced shallot along with a small spoon of butter, approximately 1 tablespoon. When the butter melts, add about a half cup of sliced mushrooms — you can use button, shiitake, crimini, oyster, or pretty much whatever looks good at the supermarket.
Sauté the mushrooms for a few minutes, then deglaze the pan with a healthy splash of cabernet sauvignon — about 3 ounces, or about half a glass of wine — and reduce by half. Then add the same amount of beef or chicken stock and reduce that by half, too.
Add a pinch of salt and some cracked black pepper as well as a handful of chopped herbs — parsley, chives, tarragon, or all three.
Finish by swirling in another tablespoon of butter, then spoon the sauce over your sliced steak and eat immediately.