the eggs are beaten until warm and then again beaten until cold again.To do this, put them in a heatproof bowl that you then place on a water bath. The easiest way to do this is to fill a pot about halfway with hot (no longer boiling) water and place the bowl on top. The bottom of the bowl should not touch the water.Beat the eggs together with the salt. Once they are a little foamy, add the vanilla sugar. Gradually add the sugar while continuing to beat the eggs. Then add the lemon zest or the lemon sugar.When the mixture reaches about 104° F (40° C), remove the bowl from the water bath and continue beating until it reaches room temperature (about 68° F / 20° C). During the cold beating, which takes at least 10 minutes, preheat the oven: 25° F/ 165° C convection oven, 355° F / 180° C conventional oven.When the eggs are cool again, sift the flour and starch over them and carefully fold them in. Then add the melted butter, which has cooled down again, and fold it in as well. Cover the bottom of a 10,25" / 26 cm springform pan with baking paper, do not grease the edges, so that the wiener mixture can hold on to them while baking. Bake for about 28 - 32 minutes.After baking, let the base cool completely on a cooling rack.
For the vanilla cream
which is needed for the butter cream, stir the starch, sugar, vanilla extract, egg yolk and salt into the milk in a saucepan until everything is smooth. Then thicken over medium heat while stirring and then let cool. Pass through a sieve.
For the buttercream
beat the softened butter in a stand mixer until it becomes light and creamy, almost like whipped cream. Then add the sifted powdered sugar a spoon at a time, while continuing to beat the butter. Then gradually add the salt, vanilla and vanilla cream as well. Add orange juice or Cointreau to taste.
Assemble the cake
Cut the wiener base twice and cut out small bases from the individual bases with a 5,5" / 14cm cookie cutter. If you don't have such a cookie cutter, use a cup coaster of about 5,5" / 14 cm and cut out the small cakes around it. Place the remaining base in a bowl and mix together with 300g of the buttercream until smooth. Assemble a cake from the small cake bases. Put some tangerines on the first cake layer, spread some of the buttercream on top, smooth it down and put the next cake layer on top, put tangerines and buttercream on top and put the lid on. Spread buttercream on the edge and on the top. Add the remaining mandarins, cut into small pieces, to the sponge and buttercream mixture and mix in. Place the cake mix around the small cake to form the basic pumpkin shape and smooth it out. Then chill in the refrigerator until firm. Then put another good layer of buttercream on top and smooth it out as well. This way you can better shape the pumpkin and the tangerines don´t moisten through. Then let it set again in the refrigerator.While the cake is setting in the refrigerator, you can prepare the marzipan paste for the decoration. For this, knead the marzipan. Then take off about 50 - 100g for the stem and the face. Color the largest part orange. Add the color little by little and knead everything well in between until you have reached the desired color intensity. Then powder the marzipan well with powdered sugar and roll out to the required size. Roll onto the rolling pin and unroll again over the cake. Carefully press down from top to bottom and then shape the pumpkin as desired. Color a piece of the marzipan green, shape stem from it and attach to pumpkin. If desired, color a small piece of marzipan black, shape it into eyes and mouth, and also attach to the cake-pumpkin. Refrigerate until ready to serve.