1. Preheat the oven to 240 degrees. Lightly brush pizza shell with olive oil.
2. Pour remaining oil into a skillet over medium heat. Add mushrooms, and sauté until tender.
3. Add spinach, and sauté just until it wilts. Season with salt and pepper.
4. Spread the mushroom and spinach mixture over the pizza shell.
5. Slice cheese into rough slices, and spread evenly on top of the pizza.
6. Top the pizza with diced tomatoes.
7. Bake until golden brown and the edges begin to crisp. Remove from the oven, and drizzle with additional olive oil before serving.