Preheat the oven to 200°C/gas mark 6. Put the potatoes in a roasting tin and toss with the oil. Season, then roast for 20-25 minutes, until crispy on the outside and soft on the inside.
Leave to cool for 10 minutes, then use a teaspoon to scoop a little flesh from the top of each potato. Spoon a little soft cheese into the holes and top with a pimento olive half. Serve just warm.