1. Lightly butter outside of potato and sprinkle with salt. 2. Wrap potato in aluminium foil and place in oven preheated to 220ºC for 20 minutes. To test if potatoes are cooked, pierce with a skewer. The skewer should pass easily through potato. 3. To serve, remove potato from oven cut star cross into top of potato and push all four sides in at once. Add a dollop of sour cream and garnish with chopped chives.