1. For the pizza bases: Dissolve the yeast in the water. Add the oil, salt and flour (reserve some of the flour for later). Knead the dough well. Let the dough rise in a warm place for approx. 30 min.
2. For the tomato sauce: combine the tomato puree with the onion, water, oregano and salt.
3. Tip the dough out onto a floured surface and knead thoroughly. Add the rest of the flour as needed.
4. Divide the dough into 4 parts and roll out each one into a thin, round pizza base (approx. 8½ inches in diameter).
5. Place the pizza bases on 2 pieces of baking parchment. Spread tomato sauce on the bases and sprinkle with cheese.
6. Coat the potatoes in oil and arrange on the pizza bases, overlapping slightly. Sprinkle with salt and bake 2 pizzas at a time in the middle of the oven.
7. Take them out after approx. 15 min. Sprinkle with half the pepperoni, then finish baking the pizzas. Garnish the 2 hot pizzas with fresh oregano leaves and serve immediately (½ a pizza per person). Meanwhile, bake the last 2 pizzas and serve as desired!
All 4 pizzas can be baked at the same time on the fan setting at 430°F. Instead of making the tomato sauce yourself, you can use a ready-made pizza sauce – approx. 8½ ounces.