Boil a large pot of salted water. Add in potatoes and cook for about 15 minutes or until tender but still firm. Drain, cool slightly, and peel. Season with salt, then mash potatoes with fork, masher, or in ricer. Place in large bowl, and mix in egg and olive oil. Knead in enough flour to make a soft dough. On a floured surface, roll dough into a long rope. Cut the rope into 1/2-inch pieces. Bring a large pot of lightly salted water to a boil. Drop in gnocchi, and cook until they float to the top, about 3 to 5 minutes. Serve with pasta sauce.