Special equipment: 9 by 13-inch Swiss roll or jelly roll pan
Prepare the Shortcrust Pastry, recipe follows, and chill.
Meanwhile, heat the olive oil in a wide, heavy-bottomed frying pan, and then add the onions. The pan will seem quite full at first, but the onions will melt down considerably after about 10 minutes.
Stir the onions in the oil, and cook over a low heat, covered, for at least 20 minutes, stirring continuously and scraping the base of the pan every few minutes.
Now add the garlic, herbs, salt, pepper, and sugar, and continue cooking until the onions begin to melt and turn golden, about 10 minutes. Season with salt, and black pepper, to taste, adjusting if necessary, and remove from the heat.
Preheat the oven to 350 degrees F.
Remove the pastry from the refrigerator, uncover and, with a lightly-floured rolling pin, roll out on a floured work surface into a rectangle to fit the Swiss roll or jelly roll pan. Lift the dough onto the tin, and prick the whole base with a fork. Bake in the oven for 10 minutes, and then remove.
Cover the pre-baked base with an even layer of onions. Arrange the anchovy fillets in a lattice pattern over the onions, placing a whole or halved olive within each diamond.
Return the pan to the oven, and bake for an additional 25 minutes to allow the flavors to blend. Serve the dish hot or cold.
Place the flour, salt, and butter in a food processor and whiz or pulse briefly. Add half the beaten egg and continue to whiz. You might add a little more egg, but not too much as the mixture should be just moist enough to come together.
If making by hand, rub the butter into the flour until it resembles coarse bread crumbs. Then, using your hands, add just enough egg to bring the dough together. With your hands, flatten out the ball of dough, until it is about 3/4-inch thick, and then wrap in plastic wrap or place in a plastic bag, and leave in the refrigerator for at least 30 minutes or, if you are pushed for time, in the freezer for 10 to 15 minutes.
Makes 1 crust (about 14 ounces).
Recipe courtesy of Rachel Allen