In a medium container, mix the sliced mushrooms with liquid aminos, maple syrup, nutritional yeast, onion powder, garlic powder, smoked paprika, and smoked pepper. Let the mushrooms marinate for 30 minutes.
Preheat a griddle to medium-high heat. Place the marinated mushrooms on the griddle (without oil) and cook for a few minutes on each side. Once they have a good color, add about 1 tbsp of oil and a few teaspoons of the leftover marinade. Continue cooking for a few more minutes until the mushrooms develop a deep, dark color.
Remove the mushrooms from the griddle and place them on a warming rack to cool. As they cool, the mushrooms will harden and become crispy.
Butter a few slices of Texas toast and toast them on the griddle until golden.
Spread Duke’s mayonnaise on the toasted bread, then layer with lettuce, tomato slices, and the cooked mushrooms.
