Preheat oven to 425F. Thaw and squeeze out frozen spinach. Mix with ricotta cheese, oregano, 4 oz of mozzarella cheese, and Parmesan cheese. Crush the garlic clove and add to spinach mixture.
Brush the pizza crust with olive oil and place on a pizza pan., Spread spinach mixture on top and sprinkle parmsean cheese on top. Slice tomatoes very thin and lay on top. Bake 15 minutes or until cheese is golden brown.