In a medium size saucepan add 12 egg yolks, 250g sugar, 50g sifted cocoa powder, 40g chocolate powder pudding. Add about 100g of milk and whisk until everything is unified and smooth, whisk in the remaining 300 ml of milk.
Cook over medium heat (5 out of 10) whisking constantly until the mixture starts to thicken up, the temperature reaching 80ºC (176ºF). Reduce heat to medium low (3 out of 10) and cook for another 2-3 minutes, keep whisking constantly. Take it off the heat.
Add 200g of chocolate and 180g of butter to the hot mixture. After everything is melted whisk until fully incorporated.
Cool it in a water bath and bring the mixture to room temperature. You have to stir frequently to avoid forming the crust on a surface and to speed up cooling process.
Tightly press the stretch wrap film on top of the buttercream, sealing it up and refrigerate for a minimum of 2 hours.
Sponge Cake Layer
Preheat the oven at 180 ºC (355 ºF), rack in the middle.
Butter 28 cm (~10.5 “) spring form cake pan and line the bottom with parchment paper.
Prepare 3 separate small bowls with dry ingredients: 75g sugar, 15g cocoa, 15g ground almonds.
In a medium size mixing bowl beat 3 egg whites on a medium speed until they form soft peaks. At high speed gradually beat in 75g of sugar until the whites are stiff and shiny.
Sift in 15g of cocoa powder and add 15 g of ground almonds. Gently fold it in by using a silicone spatula.
Pour the batter to the spring form pan, level off and smoothen the top.
Bake for 20-30minutes or until the sponge cake springs back when lightly pressed in the middle.
Transfer to the cooling rack, unmold after 5 minutes. Use a sharp knife to separate the cake layer from the mold’s side. Let cool completely, do not remove parchment paper.
Repeat the same process with 3 more cake layers.
Raspberry Filling
In a medium size saucepan add 400g frozen raspberries, 130g sugar and 165g water. Bring to boil over medium heat (5 out of 10), stir occasionally, Cook for 2-3 more minutes and then take it off the heat.
Prepare two small mixing bowls. In one whisk together 40g raspberry (or vanilla) pudding powder and 100g water. In the second bowl sprinkle 5g of unflavored gelatin powder over 35g of cold water. Let it stand about 5 minutes until gelatin absorbs the water.
Add pudding to the raspberry mixture and cook over medium heat (5 out of 10) for 2-3 minutes, until it starts thickening up. Add hydrated gelatin, stir constantly until gelatin dissolves, about 2 minutes. Do not let it become too hot and simmer!
Let the filling cool to about 30ºC (86ºF). The filling has to be warm enough so can easily spread, but not to melt butter chocolate cream that will be layered over! The easiest way to accomplish this is to cool it off in a water bath and stirring occasionally.
Cake Assembly – Day 1
Using 7.5 cm (3″) wide parchment paper strip line up the side of 28 cm (~10.5 “) spring form cake pan.
Using a hand held mixer at medium speed mix the chocolate buttercream for few minutes until light and fluffy.
Divide, cover and refrigerate 150g of chocolate buttercream that will be later used for the cake side layer and decoration. The reminder of chocolate buttercream divide into 3 equal parts that will be used for the cake filling layers (approximately 350g each layer).
Divide the raspberry filling into 3 equal parts, approximately 260g per layer.
Center and lay the first cake layer on the bottom of the spring form, paper down (the parchment paper will remain attached to the cake layer).
Use a silicone spatula to evenly spread out the chocolate buttercream layer, smoothen the top.
Top it up with raspberry filling layer. Best approach to the application is to spread small patches of raspberry filling across the surface and then with silicone spatula carefully smoothen and spread these patches until making a continuous and thin layer on top of the chocolate buttercream layer.
Center and lay the second cake layer, paper on the top. Carefully peel off the parchment paper.
Repeat the process of first adding the layer of chocolate buttercream followed with the raspberry filling layer.
Center and lay the third cake layer, paper on the top. Carefully peel off the parchment paper.
Repeat the process of first adding the layer of chocolate buttercream followed with the raspberry filling layer.
Center and lay the fourth cake layer, paper on the top. Do not peel off the paper, cover the cake tightly and refrigerate overnight.
Cake Assembly – Day 2
Remove the ring of the spring form pan and peel off the parchment paper strip from the side and the top of the cake.
Using a large cutting board or flat plate turn the cake upside down, remove the bottom of spring form pan and peel off the parchment paper.
Cover the bottom of the cake with 4 large pieces of parchment paper and invert the cake on a serving plate.
Note: These parchment papers are temporary protection for the serving dish from buttercream coating and chocolate glaze after which the papers will be removed.
Use approximately 100g of saved chocolate butter cream to thinly coat the top and sides of the cake. The purpose of this application is filling any crevices and voids before application of the chocolate glaze. Cover the cake and refrigerate.
Over double boiler melt the chocolate, stir in the butter until smooth and uniform. Let the chocolate glaze cool to about 40ºC (104ºF) before application.
Pour the chocolate glaze in a slow and sweeping round motion by creating a wide ring that will coat most of the cake top and some will spill over the side edges. Most of the chocolate will be on top of the cake.
Use an offset metal spatula to coat and level off the glaze on the top in one pass, sliding the spatula across the cake. Some of the chocolate will spill over and bleed down the cake sides. Use metal spatula to recover the spilled chocolate and glaze the cake sides until fully covered. You have to work fast before the chocolate hardens up!
Put the cake aside for an hour until the chocolate glaze is set.
Carefully remove parchment papers from the bottom and clean up the plate from any remaining spills.
Sift cocoa powder across the top of the cake.
Using a wire cake cutter carefully imprint thin grooves in the cake top, marking up 16 equal sections.
Use a tip of wetted finger to remove cocoa powder at the back in each of 16 sections. This is to allow for a proper bond between a buttercream and rosette decoration that follows.
Use remaining chocolate buttercream and pastry bag fitted with 9/16″ star tip and pipe 16 large rosettes around the cake perimeter.
Cover the cake and refrigerate.
To cut the cake use warmed up knife and wipe it off with paper towel after each cut. The knife can be warmed up by being placed in a container filled with hot water.