In this delicious recipe, two slices of brioche are dipped in a mixture of egg, milk, orange and lemon zest, and liqueur before frying, and are then covered with sauteed Bosc pears. Pears improve in both texture and flavor with time. Test for ripeness by pressing the flesh near the stem; it should yield to slight pressure. Store at room temperature until ripe, then refrigerate. For crisp, puffy French toast, make sure the oil is very hot, but not smoking. Drop a small amount of the egg mixture into the pan. If it sizzles, the oil is ready to use. Serve hot, with confectioners' sugar sprinkled on top or doused with maple syrup.