For the Crust: Heat the oven to 425F. Bake the potatoes until tender, about 50 minutes, or bake in the microwave. Peel and mash the potatoes. Combine them with the egg, ricotta, and flour, mixing with your hands until you have a soft, pliant dough. Press the dough into the bottom of an 8-inch springform pan, and bake until its firm but still springy, about 20 minutes. Take it out of the oven and let it cool. Dont turn off the oven. Filling: In a large skillet or saute pan, melt the butter or heat the oil. Add the leeks, onions, and salt, and saute until very soft, about 15 minutes. In a mixing bowl, beat together the egg and egg yolk, the evaporated skim milk, and flour. Make sure there are no lumps. Spread the sour cream over the potato crust and sprinkle the chives evenly on top. Pour in the egg mixture, and place the pie in the oven. Bake until the filling has set, about 50 minutes. If the top starts to brown before the custard has set, cover the pie with foil and continue baking until a knife stuck into the center comes out clean. Let it sit 10 minutes before serving. Serve hot, room temperature, or cold. Source: The Essential Vegetarian Cookbook by Diana Shaw, 1997 ISBN 0-517-88268-x (paper), 0-517-59989-9 (hardcover). PER SERVING: CALORIES 335, PROTEIN 15.6 G, CARBOHYDRATE 52.7 G,FAT 78 G, CHOLESTEROL 161 MG, SODIUM 110 MG, 20 % CALORIES FROM FAT. Notes: EQUIPMENT: 8-inch springform pan. Do AHEAD: you can make that crust up to 2 days in advance in. REFRIGERATION/FREEZING: refrigerate up to 3 DAYS. FREEZE indefinitely. Recipe by: Diana Shaw, The Essential Vegetarian Cookbook,pg. 350