1 Heat the oven to 200°C (180°C in a fan oven), 400°F, gas 6 and grease a baking dish.
2 Cut the tops off the tomatoes and hollow them out. Place in the prepared baking dish.
3 Mix together the egg yolks and the butter. Stir in the cheese, basil and the mascarpone and season with salt, ground black pepper and a pinch of nutmeg.
4 Beat the egg whites with a pinch of salt until stiff. Place the egg whites on top of the egg yolk mixture, sieve the flour on top and gradually mix everything together.
5 Transfer the mixture into the tomatoes and bake for 15-20 min until golden brown. Arrange on plates and serve garnished with basil.