Place a pizza stone, baking tiles or an inverted baking sheet on the lowest rack of a cold oven; preheat for 30 minutes to 260ºC or the highest setting. For each of the artichokes, peel away and discard the tough outer leaves, snapping them off at the base, until you reach the pale yellow leaves with the darker green tops. Slice off the darkest green top and rub the artichoke with the cut side of the lemon half. With a paring knife, trim the artichoke where you snapped off the leaves, removing any green portions. Rub with lemon. Trim the bottom 1 cm off the stem and pare away the tough outer skin. With a melon baller or paring knife, remove the fuzzy choke from the center of the artichoke. Cut the heart into quarters, then cut each quarter into 4 pieces. Squeeze the lemon into a bowl of water and place the artichoke pieces into the acidulated water to keep them from turning brown. Heat a skillet over the medium heat, add pacetta and cook, stirring until golden about 4 minutes. Drain the pancetta on paper towels. Pour off fat from the skillet. Add 1.5 tsp. of the olive oil and onions to the skillet. Cook, stirring occasionally, until the onions are soft but not brown, about 3 minutes. Add the drained artichoke pieces and stir to mix well. Add pepper and two third cup water. Cover and cook over low heat until the artichoke pieces are tender and most of the liquid has cooked away, about 15 minutes. Add leeks and stir to mix well. Taste and adjust seasonings, adding salt if desired. Let cool completely. Here we go with the dough again...Place dough on a lightly floured surface and pat into a disk. Use a rolling pin or your hands to roll or stretch the dough into a circle that is 1 cm thick and 10 to 30 cm in diameter. Transfer to a semolina or cornmeal dusted pizza peel or inverted baking sheet. Brush the dough with a little of the remaining olive oil. Distribute the artichoke mixture over the dough. Sprinkle the cheeses over the artichoke mixture. Drizzle with the remaining olive oil. Carefully slide the pizza onto the heated pizza stone and bake for 6 to 8 minutes, or until the bottom is crisp and browned and the top is bubbling. Entered by: Diane Pahl (1: 20.083333333333) Recipes from: Eating Well, The Magazine of Food and Health (tm) ISSN 1064-16399