Butter; to grease the foil 16 tb Unsalted butter; softened 2 c Sugar 8 oz Bittersweet chocolate - melted and slightly cooled 2 ts Vanilla extract 4 Eggs 1 c Unbleached all-purpose flour 1 ts Salt 1 c Chopped walnuts 2 c Semisweet chocolate 2 c Milk chocolate 2 c Butterscotch bits PREHEAT OVEN TO 350F. Line an 8 3/4-by-13 1/2-inch glass or metal pan with