Heat the oil in a large frying pan with the garlic for 15 seconds, then add the spinach and cook over a high heat for 1–2 minutes until just wilted. Season lightly with salt and pepper.
Heat a baking sheet in a preheated oven, 240°C (475°F), Gas Mark 9. Place 1 pizza dough ball on the base only of a well-floured, 23 cm (9 inch) loose-bottomed tart tin. Push down on the dough with your fingertips, pressing it out to fill the base, leaving the border slightly thicker. If you get any tears, forcefully pinch the dough around the hole back together.
Spoon 3 tablespoons of the passata over the base and scatter with a quarter of the mozzarella, spinach and olives. Crack 1 egg on to the pizza, drizzle with oil and season lightly with salt and pepper. Brush the border with oil to glaze. Remove the baking sheet from the oven, slide the tin on to it, then quickly return to the oven. Bake for 7–8 minutes until crisp and risen. Serve immediately. As the first pizza cooks, prepare the next for the oven.