Heat the oven to 220C/200C fan/gas 7. Rub the olive oil over the potatoes and put on the top shelf of the oven. Bake for 20 mins.
Turn down the oven to 190C/170C fan/gas 5 and bake for 45 mins-1 hr until the skin is crisp and the flesh soft.
Cut a cross on top of each potato, squeeze the sides, add the soured cream and your favourite toppings.