Preheat the oven to 400 degrees. Scrub the potatoes and poke all over with a fork. Place on a baking sheet and bake for 1 hour. Remove the potatoes and peel the skin off. Mash the potatoes in a bowl until there are as few lumps as possible.
In another bowl, add the flour and seasonings, mix, and make a well in the center. Add the potatoes and slowly mix together to form a smooth dough. Add more flour if needed.
Dust a work surface with more flour, take sections of the dough, and roll out into a ½ inch thick rope. Cut the rope into ¾ inch long pieces. Take each piece and pinch the ends to form an oval ball, and roll with the tines of a fork to get a striped design on one side.
In batches, drop the gnocchi into heavily salted boiling water and scoop out with a slotted spoon after they rise to the surface. Keep warm in a bowl in the oven.
Meanwhile, heat the tomato sauce, basil and soy milk in a saucepan over low heat until it begins to bubble. Add more soy milk for a lighter, creamier sauce. Pour the sauce over the gnocchi, toss and serve.