Heat a pan over medium heat with a tablespoon of oil.

Add sliced mushrooms and red onions to the pan and sauté for 5-7 minutes until they are tender and slightly caramelized.

Add Mexican seasoning to the mushrooms and onions, stirring well to coat them evenly. Cook for an additional 2 minutes.

While the mushrooms and onions are cooking, grate the cheese and set it aside.

Lay out the taco boats on a flat surface.

Place a layer of lettuce leaves in each taco boat.

Add the cooked mushrooms and onions evenly over the lettuce.

Slice cherry tomatoes and add them on top of the mushrooms and onions.

Sprinkle the grated cheese on top of the tomatoes, mushrooms, and onions.

Serve immediately.