1) Preheat the oven to 150C/Gas 2. Bake the potatoes for approximately 1 to 1 1/2 hours, until tender. Allow to cool before handling.
2) Scoop each potato out of its skin into mixing bowl and mash to a fine consistency.
3) In a separate bowl, combine egg yolks, melted butter, salt, pepper and nutmeg.
4) Add the egg mixture to the potatoes and mix together.
5) Add flour to mixture, half at a time, and mix until smooth.
6) Scoop out and make finger sized rolls on a floured board. Cut into bite sized pieces. Roll each piece over the back of a fork to make a round form. Freeze until hard enough to handle, and put into portion sized bags.
7) Fill a large pot with water and add a pinch of salt and boil. Drop gnocchi into boiling water 3 or 4 at a time so the water doesn't stop boiling. The gnocchi is ready when it floats to the top. Drain gnocchi, ladle into a serving bowl and add sauce. Add plenty of fresh Parmesan just before serving.
To make the Sauce:
1) Pour the tomatoes into a shallow dish, cut in half, remove the seeds and chop into small pieces. Drain off the juice and reserve.
2)In a saucepan, add olive oil and garlic and saute for 1 minute. Add the tomatoes, salt, pepper and chilli and bring to a simmer for 5 minutes. If necessary, add the reserved juice. Add the basil. Stir in the cream.