In a large non-stick pan, cook the pancetta and onion in butter over medium heat until the onion is translucent, about 5 minutes. While the onion cooks, mix together the eggs, cream, Parmesan cheese, basil and chilli flakes.
When the onion and pancetta are cooked, add the tomatoes and cook for about 2 minutes until warmed through. Add the egg mixture and stir lightly and constantly while the eggs cook. Turn off the heat when the eggs are just set and remove from the heat. Season with salt and pepper and serve.