Preheat oven to 400 degrees F.
In a bowl combine ground beef, oregano, basil, salt and pepper and mix well.
You can either make one large pizza or 4 individual mini pizzas (which are easy to freeze for later).
Using your hands form the pizza "crust" making it about half an inch thick.
Place onto a baking sheet lined with parchment paper.
Place in the oven for 10 minutes.
Meanwhile, prepare the toppings.
Wash and slice mushrooms.
Wash and dry spinach if using fresh.
Heat a large pan greased with the ghee or butter and add the crushed garlic. Cook for 1 minute.
Add the mushrooms and cook for 5 minutes, stirring frequently.
Toss in the fresh spinach and cook for 1 minute more.
Season with salt and pepper to taste.
If using frozen spinach make sure it is defrosted and squeeze any excess water out before cooking.
Remove the pan from the heat.
When the meat crust is cooked, remove it from the oven and spread pesto sauce on top. Add half the mozzarella cheese and all the spinach and mushrooms.
Finish with remaining cheese and return to the oven for 5 minutes or until the cheese is melted.