Wipe shiitake mushrooms clean with a damp paper towel
Trim off the tough stems
Slice the caps if desired
Heat a pan over medium-high heat
Add oil or butter
Add the shiitake mushrooms in a single layer
Cook without stirring for 2 to 3 minutes
Stir and cook until browned and tender, about 5 to 8 minutes total
Season with salt and pepper
Add garlic, soy sauce, or herbs if desired
Serve hot