Heat the oven to 220C/200C fan/ gas 8. Tip a layer of rock salt onto a baking tray and sit the potatoes on top. Roast for 50 mins-1 hr or until tender when a cutlery knife is inserted. Leave to cool for 10 mins, then peel off the still warm skins. Pass the potatoes through a ricer or push through a sieve using a spoon onto a work surface, then leave to cool. Add the flour, egg and 1/2 tsp salt to the potato and gently bring everything together using your hands until you have a uniform dough – don’t overwork it. Divide the dough into four. Roll each piece into a long sausage on a lightly floured surface to around 2cm in diameter. Cut each one into 1.5-2cm nuggets. You can keep them like this or roll ridges onto to them with the back of a fork or a ridged pasta paddle. Set aside on a baking sheet dusted with semolina.

For the sauce, blitz the canned tomatoes using a jug blender or hand blender. Heat the oil in a large pan over a low-medium heat, then add the onion and a pinch of salt and fry for 10-15 mins until softened and translucent. Tip in the garlic and chilli and cook for 1 min, then add the sugar, blitzed tomatoes and herbs, and bring to a simmer. Cook, uncovered, for 20 mins, stirring regularly. Season to taste.

Bring a large pan of lightly salted water to the boil. Add the gnocchi in two batches and cook for 2-3 mins or until they bob to the surface. Drain the gnocchi in a colander, then toss in the pan with the tomato sauce. Spoon onto a large sharing plate, then top with the basil, grated cheese and a drizzle of olive oil. You can open-freeze the gnocchi on trays, then store in sandwich bags for up to three months, which can then be cooked for 3-5 mins from frozen.