pour rest of mixture onto top layer of crackers. you can add a third layer of crackers if you wish, i prefer not to.
bring sugar, milk, and cocoa to good boil, cook 1 minute. add butter and vanilla.stir until a little cooled, pour over crackers. (i added some graham cracker crumbs on top while the chocolate was still hot) refrigerate until Chocolate has hardened a bit, or over night. serve chilled. keep leftovers refrigerated.