Place a heavy frying pan over medium heat and let it heat up. Add the butter and tip the pan so the butter sizzles but doesn’t burn. Add the shallot and cook briefly until it softens, then add the mushrooms and cook until they’re just short of done.
Using a slotted spoon, remove the mushrooms from the pan, leaving the butter and mushroom juice. Turn the heat to high. Add the steaks and sear on both sides. (This recipe will produce rare to medium-rare steaks; if you or your date likes – shudder – well-done beef, you can butterfly that steak, put it in the pan first, and cook it with a cover on until it’s done through before you add the good steak.).
Remove the steaks from the pan. Add the brandy and a lot of black pepper, and cook down until it’s syrupy.
Put the steaks and the mushrooms back in the pan and let them all cook together for a few minutes, until the steaks are done to your liking and hot through, and the flavors have all blended.