Preheat the oven to 240°C/gas mark 8. Place the pizza bases on two large baking sheets. Spread the passata equally over the 4 bases.
Put the spinach in a microwave-safe bowl. Cover with clingfilm, pierce, and cook on medium power for 30 seconds, until wilted. Squeeze out the excess water then scatter it over the pizzas along with the red pepper slices.
Crack 1 egg into the middle of each pizza and scatter over the mozzarella. Bake for 10 minutes, until golden and the egg is cooked through.