Bring a large pot of salted water to a boil. Drop in potatoes and cook until tender but still firm, about 15 minutes. Drain, cool slightly, and peel. Season with salt, then mash potatoes with fork, masher, or in ricer. Place in large bowl, and stir 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.
