Remove the stems of your mushrooms and gently brush and rinse to clean and pat completely dry.
Prick each mushroom gently with a fork several times to help the marinade evenly penetrate the mushrooms.
In a shallow dish add the coconut aminos, oil, and all seasonings including the sesame seeds.
Place your mushrooms into the dish and baste or brush them all over with your marinade.
Allow them to rest in the marinade for 15 minutes, flipping halfway.
Meanwhile, heat a clean grill pan or an outdoor grill over medium heat.
Grill your marinated mushrooms for about 5 minutes, or until they are just becoming tender, flipping halfway.
Over the last minute of grilling, brush them again with any marinade left at the bottom of the dish.
Sprinkle with red pepper flakes if you desire a little kick.
Slice and serve while hot.