Put the potatoes in their skins snugly in a large pot of water with 2 fistfuls of sea salt. Bring to the boil over high heat and cook for 35–40 minutes or until cooked through. Drain well, cool for 10 minutes, then peel the potatoes.

Pass the potatoes through a ricer (or use a potato masher) and allow to cool for 5–10 minutes.

Heat oil in a large heavy-based frying pan. Add the garlic and cook over medium-low heat until pale golden (about 30 seconds). Add the cherry tomatoes (whole) and cook for 10–15 seconds in the garlic oil, then turn up the heat and pour in the wine. Bubble the alcohol over medium-high heat for 1–2 minutes, add water, turn down heat and cook for 20 minutes.

Bring a large pot of salted water to the boil for the gnocchi.

To the cooled riced potatoes, add the egg yolk and a small pinch of salt and pepper and mix through. Gradually add the flour until you have a soft, pliable dough that is not tacky.

Cut the dough into 4–5 pieces, roll into logs on a floured surface and cut each log into 2–3 cm pieces. Optionally roll over the tines of a floured fork. Dust a tray with flour and set the gnocchi aside.

Blend the sauce in a food processor until smooth. Pass through a sieve back into the pot. Return to a gentle simmer, season, then add the prawns, cook for 1 minute, turn off the heat, cover with a lid and allow the steam to finish cooking the prawns.

Drop the gnocchi into the boiling water. After a few minutes they will float to the surface. Scoop out with a slotted spoon and drop into the cherry tomato and prawn pot, stirring gently.

Serve into bowls with fresh chives and freshly ground white pepper.