1. Preheat the oven to 180°C (350°F). Grease and flour three springform tins (15cm)* and set them aside. Mix and sift the flour, cornstarch, baking powder and salt and set aside.

2. In a large bowl mix the butter and sugar on high speed until light and fluffy. Add the eggs one after another and mix in well. Mash the bananas and add them together with the vanilla extract to the bowl and mix them in. Add the flour mixture alternating with the buttermilk in two portions, and mix in until just combined – do not overmix. Divide the batter between the tins and bake them for about 27-30 minutes or until a toothpick inserted in the center comes out clean. Take out of the oven and let cool down in the tins for some time, then remove and let cool down completely on a wire rack.

3. For the strawberry filling wash and dice the strawberries. Add together with the sugar to a saucepan and heat up. Let them cook for about 5-8 minutes until softened. Remove from the heat and let cool down completely. If there is too much liquid, drain.

4. For the pineapple filling drain the pineapples and dice. Add together with the sugar and cornstarch to a saucepan and heat up. Let cook for about 2-3 minutes until thickened. Take off the heat and let cool down completely.

5. For the buttercream, add the egg whites and sugar into a heatproof bowl and place it on a pot with simmering water. Whisk constantly until the mix reaches a temperature of 160°F (71°C). Use a thermometer to check the temperature. If you don’t have a thermometer, check the mixture by rubbing it between your fingers. It is good if the sugar has dissolved and you can’t feel any more sugar pieces between your fingers. Remove the mixture from the heat and whisk it with your stand mixer on high speed for about 8-10 minutes until thick and glossy – the bowl of the stand mixer should have cooled down to room temperature. Reduce the speed and add the butter in small pieces. Mix well after each addition. Add the vanilla extract and mix 2-3 minutes more on high speed – you should get a fluffy and shiny buttercream.

6. For assembling the cake, place the first cake layer on a serving plate. Fill some of the buttercream into a piping bag with a large round tip and pipe a thick circle on the edge of the cake layer. This is to keep the filling inside the cake. Pour the pineapple filling into the space you created. Make sure it has the same height as the buttercream circle. Place the second cake layer on top and repeat the procedure, but this time with the strawberry filling. Place the third cake layer on top and coat the whole cake with a thin »crumb coat« layer of the buttercream. Place in the fridge for about 20-25 minutes. Take out and finish the cake with the remaining buttercream to get a nice smooth surface. Place in the fridge for about 60 minutes.

7. Chop the chocolate for the ganache and add it together with the heavy cream into a microwave-safe bowl. Microwave for 15-20 seconds, stir and microwave again until you get a nice smooth chocolate ganache. Let it cool down again. When the cake is cooled and the ganache not warm anymore but still liquid, decorate the cake with it. Start with a small amount on the edges to get the drizzle effect (works best with a small spoon), then pour the rest on top of the cake and smooth it out with a spatula. Let the ganache dry and harden.

8. Add the heavy cream and confectioner’s sugar for the decoration into a tall bowl and mix on high speed until stiff peaks form. Fill into a piping bag with a star tip and pipe swirls on top of the cake. Place a cherry on each swirl and decorate with rainbow sprinkles.