1. Preheat oven to 425 degrees Fahrenheit. Place a pizza stone on the bottom rack of the oven for at least 30 minutes.
2. In the meantime, sauté onions and garlic in a little oil until the onion has softened. Stir in the spinach and cook down for a few more minutes. Add in ricotta cheese.
3. Once the stone is hot, bake the pizza rounds one at a time for five minutes each. Spread the spinach mixture over the pizzas.
4. Fry eggs in a little oil until the whites have set. Gently place the eggs on top of the spinach mixture. Top with Gouda and mozzarella. Broil pizzas for three minutes or until the cheese has melted.