Heat oil in a 26cm non-stick ovenproof frying pan over medium heat. Add the tomato, oregano, salt and pepper and cook, stirring, for 1 minute. Add the spinach and cook for 30 seconds, or until wilted.
Whisk together the eggs, cream, Parmesan, salt and pepper and pour into the pan. Move the mix around gently with a spatula to cover the base underneath the tomato mixture. Spoon over the ricotta.
Transfer to oven and cook for 20-25 minutes or until golden and set. Set aside for 5 minutes to cool slightly.
Scatter with basil leaves and the extra Parmesan to serve.