Have to agree with Turek. A good steak doesn’t need much else than salt, pepper and maybe garlic (everything is better with garlic). However, if you are not using good steaks, marinading can make up some of the difference. In it’s simplest form, a marinade is an oil and an acid. I use a decent (not my best) extra virgin olive oil, and match my acid to the style of cooking. Trying for a southwest flavor? Use lime and lemon. Italian - balsamic vinegar. Asian - rice wine vinegar and ginger. Season your marinade in any way you want…garlic, onion, shallot, herbs, spices, etc.
Turek did leave out the pan sauce. Once you finish using his recipe (which I’ve done myself often and whole-heartedly endorse), you are left with a blazing hot pan with some of the finest tasting drippings known to carnivores. You’ll want to deglaze the pan with broth or water and wine, cognac or bourbon (too much alcohol will have too strong a flavor, IMO). While the pan is still piping hot, add the broth first and scrape up the bottom with a wooden spoon. Add the alcohol second (this helps to prevent flare ups). Throw your mushrooms in there (you can saute them in another pan to enhance their flavor, if you wish). Some whole, fresh herbs can be tossed in while the liquid reduces by at least half and removed before serving. I’m partial to bay leaf, sage, thyme, or tarragon; my own style sticks to a single herb rather than a mixture. After your liquid has reduced by 1/2 to 2/3rds, stir in a couple of pats of butter for richness, taste test for seasoning, pour over your well-rested steaks. Garnish wish some more of the herb that was used in the pan sauce and enjoy the accolades of your guests.