Take out the stems of the portobello mushrooms and remove the dark membrane inside. This tends to be a bit bitter.

Put 2 tbsp of goat cheese in each mushroom cap. Press down with a spoon until it's spread evenly.

Top with arugula, tomatoes, and mozzarella. Spray baking sheet with olive oil.

Bake for 18 minutes at 400 degree. Enjoy.