Peel the potatoes and cut into small cubes. Par-boil them for 10 minutes, then drain and blot well to absorb excess moisture. Heat a thin layer of oil in a frying pan. Add the half cooked potatoes, chopped rosemary, garlic and a litle salt. Then add as much peperoncino or black pepper as you can take. Turn the potatoes round in the oil so that they are well coated, then leave to brown over a medium heat , flipping occasionally. Keep checking so that they don’t burn or stick. After 10 to 15 minutes, when the potaroes are almost golden and crisp, add the tomatoes and olives and mix gently. Cook for a few more minutes until the tomatoes start to go limp and the skin looks a little charred.
Sprinkle the dish with the chopped parsley and serve immediately.