3 large floury baking potatoes, preferably King Edward 3 large egg yolks 5 fl.oz/142ml carton double cream 3-4 tbsp grated hot horseradish 1-2 tbsp fresh lemon juice 2 oz/50g butter
Bake the potatoes for about 1 hour until the insides are soft. Whisk the egg yolks, cream, 3 tbsp horseradish and 1 tbsp lemon juice in a large bowl. Cut the potatoes in half and spoon the insides into the bowl, reserving the skins. Mash the potato and flavourings together, then season with salt and a little pepper. Taste and add more horseradish and/or lemon juice if required. Pile the potato back into the skins, then place the potatoes on a baking tray. Loosely cover with cling film and keep them cool, not chilled.
Half an hour before serving - remove the film, dot the filling with scraps of butter and bake in the oven for 25-30 minutes until the tops are browned. Serve with a tomato salad