Preheat the oven to 180 °C.

Sprinkle a baking tray with the coarse sea salt.

Wash the potatoes and place on top of the salt on the baking tray and bake in the oven for 1 hour.

Remove from the oven. Cut the potatoes in half and using a spoon remove the soft potato, discarding the skins. Put the potato through a potato ricer while still warm and then heap onto a serving plate.

Season lightly with Maldon salt.

Place a good helping of sour cream on top and garnish with fresh caviar and chives and serve.