Making a sauce in the pan you just used to cook whatever the sauce will cover — in this case, a beautiful steak — is all about perception. It looks (and tastes) like it takes more time and training than it actually does. That's because the ingredients do a lot of the work for you — the meat, in a way, becomes part of the sauce. The fundamental technique here is called deglazing, and it's one of those essential principles of cooking that chefs hesitate to give away because it's so easy. Truth is it's simple to master, and it will catapult your confidence as a cook in just a few minutes.
The first thing to understand is that it's a blessing to have little bits of meat stick to the pan when you're cooking proteins like beef, pork, or chicken because those bits become the foundation of the sauce. The technical term for these little caramelized jewels is "fond," and their flavor is everything here. Be careful not to burn them when you incorporate them into your sauce, because then the final product will taste... burned. So keep your heat moderate. Beyond that, it's hard to mess this up. And the real beauty of deglazing lies in its speedy efficiency. By the time your steak has rested after cooking, everything's ready to eat.
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.
1. Cut shallots or onions into thin slices or small dice. Add to the hot pan after removing meat. They will release moisture, loosening flavorful bits of meat ("fond") from the pan. This is the first deglaze. A pat of butter helps, too--the milk solids will caramelize and attach themselves to the fond.
2. Add some cut-up vegetables, but nothing that takes long to cook or the sauce will evaporate and your protein will get cold. Try mushrooms, jarred artichoke hearts, or olives.
3. The second deglaze is with liquid: first some wine, then some stock (or even water). This time, scrape the pan with a wooden spoon to get all the tasty bits incorporated into the sauce.
4. Swirl in some butter, maybe a tablespoon. Use a spoon or pick up the pan and move it in quick circles over the burner. Done.