There is a small bakery called Sweet Stop on the corner of Sutter & Buchannan. It's inside a Japanese grocery store. They have the original Blum's coffee crunch and lemon crunch cakes. I don't know how they got the recipe but it's the real thing. If you call ahead, you can reserve one. The number is 415-931-8165 (or for you old time San Franciscans, that's WEst 1- 8165). No, I don't have anything to do with the shop other than I am a loyal customer. (I couldn't bake a cake to save my soul, even if I knew you were coming).