Two hours before serving, combine the marinade ingredients in a shallow dish and add mushrooms. I let them lay on their top side in the marinade, and spoon some marinade into the bottom-up side to let it soak. Marinate for two hours.

One hour before serving, preheat oven to 375 degrees F. Slice off the top of the heads of garlic and drizzle a bit of olive oil (1/2 tablespoon) on top. Wrap in foil and roast for 45 minutes. Let cool completely. Heat the balsamic vinegar in a small saucepan and bring to a boil. Reduce to a simmer and cook for 3 minutes, then turn off heat and set aside to thicken.

Slice red onion into rings and add 1/2 tablespoon olive oil into a large skillet on medium heat. Add onions and let soften and caramelize for 10-12 minutes. Set aside once finished, leaving the skillet on. Add the marinated mushrooms to the skillet top side up. Cook for 5 minutes, then flip and cook for 4 more. Turn back over, add a slice of gouda on top, and turn off heat.

Toast the English muffins. Using your fingers, squeeze roasted garlic out of the head into a bowl. Mash with a spoon. Spread on both sides of each English muffin.

Top English muffin with a portobello cap, onion rings, tomato, avocado, and butter lettuce. I recommend a light sprinkle of salt and pepper on the tomato and avocado for flavor. Finish with a drizzle of syrupy balsamic and serve.