The onions: Cook the onions slowly in 4 tablespoon of olive oil in a covered frying pan or saucepan, stirring frequently, until they are soft and thoroughly tender, but now browned--20 minutes or more. Ahead-of-time note: May be cooked ahead. Keeps in refrigerator for several days. Forming the shell. Meanwhile, butter the inside bottom (not the sides) of the jelly-roll-pan. Roll out the chilled dough into a rectangle 1/8-inch thick, and larger and wider than the pan. Fit it into the pan, and neatly trim off the overhanging edges. Fold the dough back in on itself, creating a narrow border inside the rim of the pan. Make a decorative edging by pressing the tines of a table fork into the border. To prevent the dough from rising as it bakes, prick the inside surface all over with 2 forks. Ahead-of-time note: Pastry may be made to this stage and refrigerated until you are ready to continue. Final assembly: When the onions are tender, season with salt and pepper, and let them cool. Scatter them over the inside surface of the dough. Bake for 25 to 30 minutes at 425oF. While the oven is preheating, arrange a design of black olives over the onions. Sprinkle the cheese over all, and dribble on a tablespoons of olive oil. Bake in the lower third level of the oven until the pastry has browned and is beginning to shrink from the sides of the pan. Serving: Slide onto a serving board or work surface. Cut into small, finger-sized squares. Serve hot or at room temperature. Using the same pastry shell, you can also make a quiche. Calculate the custard by egg: Whisk 1 "large" egg in a measuring cup, blend in milk or cream to reach the 1/2-cup mark. For example, whisk 3 eggs in a 4-cup measure and stir in enough liquid to reach the 1 1/2-cup mark. Whisk in a little salt and freshly ground white pepper to taste, plus perhaps a speck of nutmeg or a few drops of hot-pepper sauce. Julias Pie Crust: Pie crust dough for two 8-inch tart shells or one 9-inch covered pie, or double this for an 11 x 17-inch jelly-roll pan. The initial mixture: Place the flour, salt, and diced butter in the container of the processor and pulse 5 to 6 times in 1-second bursts, to break up the butter. Add the shortening, turn on the machine and immediately pour in 1/2 cup ice water. Pulse 2 or 3 more times. Remove the cover and feel the dough: it should look like a bunch of small lumps and when you press a handful continued in part 2