- Place potatoes in a pressure cooker with enough water to cover.
- Close pressure cooker and put in medium heat.
- Cook for 5 minutes after the regulator starts to blow steam or until tender.
- Peel potatoes and rice them using a potato ricer.
- Place riced potatoes in a large bowl and refrigerated for at least 3 hours (better if refrigerated overnight).
- Combine into the refrigerated riced potatoes the egg, margarine, salt, grated cheese and mix well while adding the flour just enough to keep mixture from sticking.
- Roll the dough on a lightly floured surface into a rope ¾-inch thick and cut into 1-inch long pieces.
- Press each piece with a fork to create a pattern and slight indentation that will hold the sauce when served.
- Boil the gnocchi in batches in plenty of salted water.
- The gnocchi are done about 2 minutes after they float to the surface, remove with a slotted spoon, and serve.