Divide the yolks from the egg whites. Then work 250g of soft butter in a planetarium and add sugar and vanilla seeds (scraped from the pod). Start to incorporate in the planetary one egg at a time and then buckwheat flour and almond flour. Now start working the snow whites with a clean whisk. When the egg whites have a firm texture, add the mixture with a spatula from the bottom to the top. Now pour the mixture into a buttered and flored baking sheet. Bake at 180°C for 45 minutes and then let cool. Once cooked and cooled, cut the cake in half and spread the crayfish jam on the inside. Serve with cream.