2) Slice the stems off of the mushrooms so they can lay completely flat. Slice each cap in half so you have 8 round mushroom slices. Carefully cut each slice into a heart shape with a cookie cutter.
3) Top half of the heart shaped mushrooms with 1 tbsp. of tomatoes and 1 tbsp. of cheese. Top with remaining mushroom slices. Brush the top side of each sandwich with olive oil.
4) Preheat a large, nonstick skillet or griddle pan. Place the mushroom sandwiches in the pan carefully, oil side down, and cook for 2 minutes. Brush the top half with oil, flip, and cook for 2 minutes more. Season with salt and pepper, to taste, and serve.