Whisk the eggs, season with salt and pepper. Wash and halve the tomatoes. Wash spinach and shake dry. Wash basil and pluck the leaves from the stalks.
Pour the egg mixture into an ovenproof dish lined with baking paper (approx. 20 x 30 cm). Arrange tomatoes, spinach and basil on top. Crumble the ricotta over it. Bake in a preheated oven (electric cooker: 200 °C/circulating air: 180 °C/gas: see manufacturer) for approx. 20 minutes.
Remove the frittata from the oven and lift it out of the pan with the help of the baking paper. Cut the frittata into pieces and serve.