In a small bowl, mix all of the mushroom rub ingredients until well combined.

Slice off the head of each mushroom, as well as, the pointy stub on the opposite end. Discard each stub and save the mushroom heads for future meals.

Rub the mushrooms with the prepared rub, covering each mushroom completely.

If using the panini grill: Heat the panini grill to medium. Once hot, add the mushrooms and close the lid. I start with my thickest mushrooms at the top of the grill and the thinnest two at the bottom. Grill the mushrooms for 30 minutes, stopping every 5 minutes to flip and rotate the mushrooms to ensure even grilling. If the mushrooms become more charred than desired, turn down the heat slightly.If using cast iron skillets: Heat one of the skillets on the stovetop over medium heat. Once hot, reduce the heat to medium-low and add the mushrooms, then top the mushrooms with the second skillet to press. If the mushrooms are of uneven thickness line them up from thickest to thinnest in the skillet. Leave the mushrooms pressing for 20 minutes, stopping every 5 minutes to flip the mushrooms, if needed, you can also rotate the skillet to ensure even cooking. Turn the heat back to medium and press the mushrooms for an additional 5 minutes on each side (if the mushrooms have charred at medium-low don‘t bother raising the heat).

Preheat the oven to 350°F.

Brush the bottom of a baking dish (I use an 8 x 8 pyrex dish, however, any oven-safe dish will work) with Korean BBQ sauce, then add your pressed mushrooms to the dish. Brush each side of the mushrooms with more sauce. Once the oven is preheated, add the baking dish to the oven and bake the mushrooms for 35 minutes.

Before serving, brush each mushroom with additional sauce. If desired, sprinkle with toasted sesame seeds and/or sliced green onions. Enjoy!