• Ideally, you make the cake base the day before, or a few hours in advance. The fine-pored biscuit sponge needs time to stabilize, so it does not start to fall apart when being cut.
• Preheat your oven to 175°C/ 347°F top to bottom heat.
• Using a stand or hand mixer, whisk together the eggs and sugar at a high speed for approximately 8 minutes. This adds air into the dough. The mass should expand and become nice and thick.
• Combine the cornstarch, flour, and baking powder and sieve it into the bowl, to avoid any lumps. Add it in little portions to the egg mass, and combine at a slow speed. (If you mix too fast the dough might collapse and end up being too hard).
• Cover your baking form with butter and dust with some flour. This will help the cake pop out easier after baking.
• Fill the batter into the cake tin and bake for approximately 30-35 minutes. To test if the cake is done, prick a skewer in the middle. If it comes out clean the cake is ready. Once the cake cooled completely, store it in the fridge until needed.

To make the German Butter Cream

• Place the cornstarch, vanilla extract, sugar, and turmeric in a bowl with 100 ml of the milk and whisk to a smooth mass, to ensure that no lumps remain.
• Pour the remaining milk into a small saucepan and bring to a boil, while stirring continuously to ensure the bottom does not burn. Once the milk is boiling, remove it from the heat and pour in your starch mixture. Mix in with a whisk and then place back onto the heat, while stirring continuously. The pudding should thicken up. You do not want the pudding to be too creamy, I prefer a drier consistency for the cream. (see picture)
• Cool the pudding to room temperature. To prevent a skin from forming, place some cling film/foil on the surface. The pudding and the butter need to have the same temperature, so it is best to keep them in the same room.
• Once both the pudding and butter are at room temperature, whisk the butter with the powdered sugar for about 3 minutes at a high speed. You will see that the butter becomes a white sheen.
• Add in the vanilla pudding spoon by spoon. Whisk on high speed to combine the pudding after each spoon.

To make the caramelized nuts

• Heat a saucepan until the sugar and butter have melted. Stir continuously.
• Add the nuts. Stir to coat the nuts with the butter-sugar emulsion.
• Spread the nuts on some baking paper and leave to cool. Once it is cooled you can break it into little pieces with a rolling pin, or grind in a food processor.

Assembling the cake

• The wreath-shaped cake needs to be sliced into three tiers. I like to use a cake leveller. Alternatively, take a spool of thread and wrap it equally around the cake. Hold it tight with both hands and pull in opposite directions so it cuts through the middle of the cake and leaves you with two perfectly even layers. Then repeat Another option is to use a paring knife to score the entire outside edge of the cake halfway up the side. Take the serrated knife and cut through the cake along the indentation made with the paring knife. Use the knife to lift the top layer off of the bottom layer.
• On each layer, first spread a layer of raspberry jam, followed by a layer of German buttercream. You will be able to achieve evenly high layers if you pipe the buttercream onto the cake layers, rather than spreading it with a pallet knife. Both ways are possible.
• After you filled the cake, place it back in the fridge for 15 minutes. This will help firm up the cake and cream and will make it easier to cover later on.
• Fill some buttercream in a piping bag with a star tip to decorate later. Evenly spread the remaining buttercream on the cake. I like then to place the cake back into the fridge for a further 15 minutes. This will harden the buttercream to avoid the caramelized nuts to get too wet. If you are planning to serve the Frankfurter Kranz the next day, only add the caramelized nuts before serving, as otherwise, they might get soggy.
• I have not found a neat way of covering the cake with the nuts. Gently add some to the palm of your hand and then press onto the cake, until it is covered from all sides.
• Lastly using the piping bags, pipe little roses on top of the cake and decorate the tips with raspberries. Store in the fridge until serving.