For the layers:
1. Preheat the oven to 180 degrees top/bottom heat. Line 3 springform pans, 15cm diameter, with parchment paper
2. Mix 300 g flour, 2 1/2 tsp baking powder & 1/2 tsp salt in a bowl and set aside.
3. Beat 150 g soft butter and 1 tbsp lemon zest until creamy in the stand mixer bowl with the paddle attachment, then add 300g sugar and beat everything airy for about 5 minutes.
4. Mix in the 3 eggs (L) one at a time, 30 seconds each on low speed. Then add 1 tsp vanilla flavoring.
5. Alternately mix the flour mixture and 60 ml lemon juice into the batter on low speed, until a smooth batter forms. Distribute the batter evenly between the 3 tins and bake in the preheated oven for 30-35 minutes. Do the toothpick test, take the cakes out of the oven, and let cool in the tin for 10 minutes. Then turn the layers out onto a wire rack and let cool completely. Then wrap in plastic wrap and store in the fridge overnight (this way the layers won't crumble when cutting and are easier to work with)
For the buttercream:
1. The next day prepare the buttercream once: Beat 225g room-temperature butter with the paddle attachment of the stand mixer on medium speed for 5-10 minutes until pale and creamy. Sift 420 g powdered sugar and gradually add it in, mixing on the lowest speed. This prevents air bubbles in the frosting. Then add 2 tbsp milk, 1 tsp vanilla flavoring, 1/2 tsp salt, and 1 tbsp lemon syrup and mix briefly again. Fill half the buttercream into a piping bag with a round tip.
2. Now take the cake layers out of the fridge and halve 2 of them horizontally. Place one halved layer on a cake board, spread thinly with buttercream, and pipe a dam around the edge with the piping bag. Now fill the buttercream ring with 2-3 tbsp lemon curd, spread the curd flat, then place the next halved layer on top and press down lightly. Spread this again with buttercream, pipe the edge with the piping bag, and fill again with lemon curd. Then place the unhalved layer on top. Spread this again with buttercream, pipe the edge, fill with lemon curd, and place a halved layer on top. Then repeat the whole thing again and finish with the last halved layer. Coat the cake thinly with the remaining buttercream, smooth it out, and chill for at least 1 hour.
3. Prepare another portion of buttercream (see step 6). Place the cake on a turntable and coat thickly with the buttercream. Then hold the Cake Scraper Style 10 against the cake, turn the turntable, and slowly scrape off the buttercream until clear grooves are visible. Wipe the cake scraper off against the bowl after each turn. Once the lines are clearly visible, chill the cake again for 30 minutes. Tint the remaining buttercream with colour mill food coloring in lemon and fill into a piping bag with a round tip.
4. Take the cake out of the fridge after 30 min and fill in the deeper grooves well with the yellow buttercream. Then run a smooth cake scraper around the cake several times, wiping off the excess buttercream against the bowl each time, until the striped pattern is visible. Chill the cake again for 30 minutes.
Finishing:
1. For the chocolate drip, bring 75 ml cream to a boil in a small pot and pour over 225g white chocolate drops. Stir well until the chocolate has melted, then add 15 g butter and mix well. Tint with 1-2 drops of colour mill and fill into a squeeze bottle.
2. Take the cake out of the fridge and coat the surface with the chocolate drip, then let individual drops of chocolate run down the side of the cake.
3. Prepare a 3rd portion of buttercream (see step 6) and divide between two bowls. Tint one half with colour mill lemon and the other half with colour mill mint. Fit a piping bag with a large star tip and fill alternately with 1 tbsp yellow and green buttercream, so a marbled cream forms. Then pipe large dots on top of the cake in circular motions.
4. Finally decorate the cake with sprinkles, crunch balls, and sugar sticks.
