- Preheat Oven to 450F.
- Wash and de-stem the portobello mushrooms.
- Place the mushrooms cap side down on a foil-lined sheet and drizzle with olive oil.
- Sprinkle with pizza seasoning.
- Layer spinach, tomato, cheese and another round of seasoning.
- Cook in oven until cheese has melted or around 6 minutes.
- Add the pepperoni and cook until the pepperoni is crispy.