If your mushrooms are dirty, allow time for wiping them clean with slightly dampened paper towels before lighting the charcoal.
Cooks' notes:
• If you aren't able to grill outdoors, mushrooms can be grilled in a hot lightly oiled well-seasoned large (2-burner) ridged grill pan over moderately high heat.
• If you aren't able to find large shiitakes, you can use smaller ones but will need to grill them on a lightly oiled perforated grill sheet to prevent them from falling through the grill rack.