4 large baking potatoes (approx. 1.3-1.5 kg)
1 egg
100g potato flour + extra for rolling out
35g grated parmesan (optional)
65g grated cheddar (optional)

1.Preheat the oven to 190C. Stab the potatoes several times with a fork, and arrange on a baking sheet. (You may like to place them on a layer of salt crystals.) Bake at 190C for 1-1.5 hours until cooked through and soft.
2.Cut the potatoes in half and scoop out the flesh. Grate the flesh by hand or using a food processor, or pass through a potato ricer. Collect the potato flesh in a large mixing bowl and leave to cool. (At this stage I had just over 900g of cooked potato.)
3.Add the egg and 100g potato flour and mix well to create a dough. If you are using the cheeses, add them now, and mix and knead to combine. The dough should be smooth and not sticky. If necessary, add a little more potato flour.
4.Dust a surface with potato flour. Break off pieces of the dough and roll out into long sausages about the thickness of a thumb. Cut each sausage into 1-1.5cm lengths, and press the tines of a fork into each piece to create ridges.
5.You can cook the gnocchi straightaway, or refrigerate or freeze them till required.
6.To cook, bring a large pan of water to the boil. Carefully add the gnocchi, and bring back to the boil. The gnocchi will float up to the surface. Once they are floating, cook for a further 1-2 minutes, then drain.
7.Serve hot with your favourite sauce.