1. Peel the potatoes and cut into 1/2 inch cubes. Place potato cubes in a saucepan and cover with water; salt to taste. Bring to a boil and cook 1 or 2 minutes; drain.
2. Heat oil in a skillet over medium heat. Add potatoes and cook while stirring and shaking pan (to prevent sticking) until golden, about 10 minutes. Add the onion, salt and pepper, stir. Add green pepper and cook while stirring for about 3 minutes. Add butter and cook 2 minutes.
3. Stir in pimento, stir, and serve.