Preheat oven to 180C

Line a baking tray with baking paper and spread evenly a thick layer of rock salt on top. Place unpeeled whole potatoes on top of the rock salt with a small gap between each potato. bake in the oven for 45 – 60 mins until soft on the inside. Remove from oven and allow to cool just enough to peel them. When cool enough peel potatoes and place flesh though a potato ricer into a large bowl. Allow potato to cool to almost room temperature.

Agg lightly whisked egg. Then add almost all the flour and salt.. Mix with your hands until the flour is moistened and the dough starts to clump together; the dough will still be a bit crumbly at this point. Gather the dough together and press it against the bottom of the bowl until you have a uniform mass. Transfer it to the floured surface and wash your hands.

Knead gently until the flour is fully incorporated and the dough is soft, smooth, and a little sticky, 30 seconds to 1 minute. (Don’t overmix it, or the gnocchi will be tough, the dough should feel very delicate.) Move the dough to one side, making sure the surface underneath it is well floured. Cover it with a clean kitchen towel.

Cover two baking trays with baking paper. Tear of a small piece of dough about the size of a small orange. With the palms of both hands, roll the dough piece on the floured surface into a rope about 2cm in diameter. 

With a sharp knife, cut the rope crosswise every 2cms to make roughly 2cm square gnocchi. Arrange the gnocchi in a single layer on the covered baking trays, making sure they don’t touch. Repeat until you run out of dough, reflouring the work surface as needed. 

Bring a large saucepan of water with a pinch of salt to a boil over high heat. Add about 1/4 of the gnocchi. To get the gnocchi into the boiling water, fold the parchment ends to form a chute and gently shake the gnocchi out, taking care not to clump them together as you drop them in. Give one gentle stir, wait until the gnocchi all float to the surface of the water, and then cook them for 1 additional minute.

While the gnocchi is cooking melt the butter in a large frying pan. When the gnocchi is cooked pick up with a slotted spoon shaking as much water off as possible and add to the melted butter. Sprinkle with a pinch salt and cook, shaking the pan occasionally to turn the gnocchi, until they’re lightly browned, about 2 – 3 minutes. Transfer to a large plate. Repeat with the remaining gnocchi.

When all the gnocchi have cooked, wipe the frypan clean with a paper towel. Add the additional butter and when almost melted add the sage leaves and cook, stirring occasionally, until the butter turns a light brown color (be careful not to let it burn) and the sage leaves darken and crisp up slightly, 2 to 3 minutes. Remove from the heat. Add the reserved gnocchi and the lemon zest to the pan and toss to coat well. Season to taste with salt and pepper. Serve immediately.