Brösel: Sponge-cake crumbs
Krokant: Crushed hazelnut brittle
German cake recipes often call for cake ingredients that you can’t find in small, rural grocery stores. Some of them are Brösel (sweet crumbs), Krokant (crushed hazelnut brittle), grated chocolate, and marzipan.
For Brösel, bake a thin, plain sponge cake (e.g. a batter made of equal parts egg, sugar and flour, and two eggshells of water: cream eggs, sugar and water together for 10-20 minutes, fold in flour) on a baking sheet (at 425ºF for about 5-7 minutes), immediately break it into small pieces and dry out in a 250ºF oven with the door propped open (30-60 minutes). Transfer the brittle pieces of sponge on a counter and use a rolling pin to crush into little crumbs.
Commercial Krokant consists of 20% hazelnut, sugar and invert sugar syrup. I made mine using leftover glaze from roasting almonds for the holidays (homemade, consisting of butter, sugar, vanilla, and salt), about half as much glaze as hazelnuts. Blanch the hazelnuts in boiling water for 3-5 minutes, then cool off rapidly in ice water or under running cold water. Pat dry and peel the skins off (e.g. by rubbing with a dry towel). Chop into little pieces (a nut grinder helps with this task). In the meantime, melt nut glaze (or just plain sugar) in a non-stick pan. Once completely melted (it will start bubbling), add the chopped nuts. All the while stir with a wooden spoon. After a couple minutes, or when thoroughly coated, pour the mixture onto a wax paper lined baking sheet and let cool off completely. Break into little pieces and run through the nut grinder once more.
If your local grocery store only offers almond paste, but no marzipan, you can make your own. Even if they do carry marzipan, it might be more economical to create your own from almond paste. Here is how. Put the almond paste in the bowl of a stand mixer, equipped with the paddle attachment. For 7oz almond paste, add 1.26oz light corn syrup and start mixing at low speed. Once almond paste and corn syrup start coming together, add about 7oz powdered sugar, a little at a time, until the marzipan has reached the desired consistency.