For sponge cakes
- Preheat oven to 180* C (350* F) Fan.
- In a bowl, combine all of the dry ingredients with a spoon; baking powder, cocoa powder and flour.
- To a mixer, add the butter and sugar. Beat on high speed with the whisk attachment, until the mixture becomes light and fluffy.
- Lower mixer’s speed and add the vanilla extract and 1 egg. Wait until it is completely incorporated before adding the next egg.
- Remove mixer from stand and add the yogurt and the dry ingredient mixture.
- Mix with a spatula until all the ingredients are completely combined.
- Grease 3 round 20 cm cake pans with butter and dust with flour. Divide mixture among them.
- Bake for 25 minutes.
- When ready, remove from oven and allow to cool completely.
- If you don’t have 3 identical cake pans, then spread the mixture in a 25×35 cm baking pan and cut into 3 equal sized cakes with a round baking ring.
For the buttercream frosting
- In a mixer, add the butter, icing sugar and vanilla extract.
- Beat for 2-3 minutes to combine.
- Finely chop the chocolate couverture, add to the frosting and mix.
- Spread a small amount of the frosting onto the serving plate so that the sponge cake sticks to it.
- Place the least presentable sponge cake layer as a base.
- Spread 1/3 of the frosting over it and smooth with a spoon.
- Add 1 tablespoon of dulce de leche and spread with a spoon.
- Cover with the second sponge cake. Add 1/3 of the frosting and 1 tablespoon of the dulce de leche.
- Repeat the same process with the final layer of sponge cake.
- Decorate with waffle pieces, pretzels and candy.
- Break up the chocolate couverture into small pieces. Place in a bowl, cover with plastic wrap and microwave for 1-2 minutes, at 800 Watts.
- Pour over cake and add sprinkles.