Cut enough bread into 1-inch (2.5 cm) cubes to measure 5 cups (1.25 L). Mix bread cubes, leeks, chicken and dill weed. Spread bread mixture in ungreased square baking dish, 8x8x2 inches (20x20x5 cm). Sprinkle with cheese. Mix remaining ingredients; pour over cheese. Cover tightly and refrigerate at least 4 hours but no longer than 24 hours.