The day I made these I couldn’t find chocolate graham crackers, so I used a whole box of Famous Chocolate Wafers, setting them on a large wire rack over an 18- by 12-inch foil-lined rimmed baking sheet. Rather than pour the butter-sugar mixture over the graham crackers, I brushed each cookie with the mixture. The rest of this recipe is the same. Using the wafers you get uniformly round cookies rather than broken pieces.