Created by lazyme on March 13, 2015
Step 1: Wash and dry mushrooms, cut off ends of stems without separating them from the caps, and slice 1/8-inch-thick lengthwise.
Step 2: Sprinkle with seasoning salt, fines herbes, and dry mustard.
Step 3: Brown in butter, adding more if necessary to keep mushrooms moist.
Step 4: When nearly done, add vinegar; reheat, and serve hot.