With the rack in the middle position, preheat the oven to 350°F (180°C).
Prick the potatoes with a fork and place directly on the oven rack. Bake for 1 hour or until tender.
Remove the potatoes from the oven, peel while still hot and press through a potato ricer. On a lightly floured surface, place the potato purée. Sprinkle with the salt. Let cool.
Sprinkle with the flour and add the egg. With your hands, gently combine the ingredients. Knead the mixture until just smooth. Do not overwork the dough. If the dough is too sticky, add flour. Shape into a disc.
Immediately divide the dough into 6 pieces. On a lightly floured surface, roll each piece into a long ½-inch (1 cm) thick rope. With a knife, cut each rope into ½-inch (1 cm) gnocchi. Lightly dust with flour. If desired, roll the gnocchi over a gnocchi board or with a fork until rounded and grooved. Set aside on a lightly floured baking sheet. The gnocchi may be frozen at this stage.
Into a large pot of salted simmering water, gently drop one-third of the gnocchi at a time. Once they float to the surface, let simmer for 2 minutes or until cooked through. With a slotted spoon, drain the gnocchi and add to warm Oregano Tomato Sauce. Adjust the seasoning.