→Start making the raspberry cream first to better synchronize the downtime in all these recipes. Then, place that in an airtight container in the fridge while making the chocolate cake layers. Then, while that is cooling down, start making the chocolate mousse.

• Directions for the Raspberry Cream
  
   
• For the raspberry cream, place your frozen raspberries into a medium bowl, sprinkle one tablespoon of sugar over the raspberries, do this step about 1 to 2 hours before you need the cream.
   
•  Let the raspberries rest until they are soft and juicy.
   
• In the bowl of a stand mixer fitted with the whisk attachment ( or in a large bowl using an electric beater), add the 500-gram cold heavy cream, one teaspoon vanilla bean paste, and two tablespoons of sugar.
   
• Whip the cream at low speed for one minute, then turn the mixer to medium and whip until fluffy, about 2-4 minutes. 
   
• Add both the juicy raspberries and the raspberry juice and combine a spatula. 
   
• For maximum freshness and deliciousness, Use immediately or store in an airtight container in the refrigerator for up to 3 hours.

Directions for the cake layers

• To make the chocolate cake layers, adjust the oven rack to the middle position and preheat the oven to 165C° /  325F° 30 minutes before baking.
   
• All the ingredients, → the unsalted butter, the eggs, plain yogurt, and sour cream, need to be at room temperature. If the ingredients are too cold, they won't emulsify or whip up with enough air to create a good rise in your chocolate cake layers. The ideal temperature for these ingredients is about 20C°/ 70F°.
   
• Use a pastry brush to lightly coat the inside of 3 x 20 cm (8 – inches) round cake pans or 3 x 20 cm (8x 8-inches) square cake pans with softened or melted butter. Next, add a few tablespoons of flour and tap it around the inside of the pan until all the buttered surface is covered then, turn the pan upside down over a sink and tap out the excess flour, and line with parchment circles. 
   
• Sift together the 350-gram all-purpose flour, two teaspoons of baking powder, and one teaspoon of baking soda in a medium bowl. Add 1/2 teaspoon fine sea salt ( omit if using salted butter). Give it a quick whisk to combine and set aside for now.
   
• In a medium bowl, add 125-gram unsweetened cocoa powder and 250 gram strongly brewed fresh coffee or espresso, give it a quick whisk until smooth, and add the 200-gram plain yogurt ( or buttermilk) and 100-gram sour cream ( or plain yogurt or buttermilk) give it a whisk until combined and smooth. The temperature should now be 22C°/71.6F°).
   
• Place the 250 gram salted or unsalted butter ( diced) and three teaspoon vanilla bean paste (or pure vanilla extract)  in the bowl of a stand mixer fitted with the paddle attachment. Turn to medium-low speed and cream the butter until fluffy, stopping to scrape down the sides and bottom of the bowl as needed, about 5 minutes. 
   
• Add the 550-gram superfine sugar ( or white sugar), and mix fluffy for about 5 minutes. Stopping to scrape down the sides and bottom of the bowl as needed, make sure to mix on medium-low speed and never on high speed. If you mix too fast or too long, you will collapse all your air bubbles, and your cake will be really dense and brick-like-not light and fluffy.
   
• Scrape down the sides and bottom of the bowl, and add the five large eggs one at a time, mixing slowly on medium speed after each addition, about 20 seconds. It´s important to add them one at a time to be completely incorporated into the batter before adding in the next.
   
•  At this stage, the mixture may look broken, which is fine ( overwhipping the eggs could cause the cake to expand too much during baking and then deflate)
   
• At this stage, when you add the flour mixture, it´s always important to mix as slowly and as little as necessary since you don't want to traumatize your batter.
   
• Add one-third of the flour mixture and one-third of the cocoa-coffee- and yogurt mixture to the butter mixture, beating at low speed until just combined—about 20 seconds. Stop scraping down the bowl as needed. Next, add another one-third of the flour mixture and one-third of the cocoa-coffee-and yogurt mixture to the butter mixture, beating until well incorporated, about 20 seconds. Stop scraping down the bowl as needed. Next, add the remaining flour mixture, followed by the remaining cocoa-coffee- and yogurt mixture, and beat just until combined—about 20 seconds. Don't over-mix.
   
• Remove the bowl from the mixer stand and scrape the bottom of the bowl to incorporate any dry ingredients that may have settled there.
   
• Divide the cake batter among the three prepared cake pans, about 675 grams spread evenly using an offset spatula. Gently tap the pans on the counter several times to release excess air bubbles.
   
• If you don't have three pans, the remaining cake batter can be held at room temperature for up to 3 hours.
   
• Bake the first two layers in the center of the oven until a wooden pick inserted into the center comes out with a few crumbs, 28 to 30 minutes. Repeat with the final layer.
   
• Let the cake layers cool in their pans on a wire rack for 10 minutes, then use a knife, loosen the sides of the cakes, and carefully turn them out onto wire racks. Peel off the parchment paper and let it cool completely.
   
• If you don't use the cake layers right away, once cool, wrap each layer tightly in plastic wrap at room temperature for up to 4 days. Or You can freeze the cooled cake layers for up to a month, wrap each individual cake layer with 2 layers of plastic wrap, followed by aluminum foil. Before using your frozen cake layers, remove the chocolate cake layers from the freezer about an hour before you plan to fill the cake. It is important that the cake layers are not completely frozen when you fill/decorate your cake. Just let the cake layers thaw for about one hour. This way, they are much easier to handle.
   
• When making this layer cake, the best thing you can do with the baked chocolate layers is to double wrap the cooled cake layers with plastic wrap and freeze them for an hour. This way, they are a bit cold and firm and easier to work with, and less chance of getting cracks in the cake layers.

Chocolate Mousse
 

• For the chocolate mousse, place 50 grams white sugar, one egg, five egg yolks, and one teaspoon vanilla bean paste in the mixer bowl and whisk to combine.
   
• Place the bowl over the pan of simmering water ( but not touching the water) and constantly whisk until the mixture is warm to the touch and the mixture looks light yellow for about 5 minutes. This step is done to ensure that the eggs are safe to consume and to dissolve the sugar, so it whips up beautifully.
   
• Attach the bowl to a stand mixer fitted with the whisk attachment, whip on medium-high speed until the mixture has tripled in volume, is thick, and foam forms a ribbon when you lift the whisk out of the bowl—about 5 minutes.
   
• Meanwhile, melt 250-gram chopped bittersweet dark chocolate 64 to 66% in a medium bowl over a pan of simmering water, Or use a small microwavable bowl, stirring with a silicone spatula every 15 seconds, and cool the melted chocolate for 5 minutes. If the melted chocolate is set up before you add the softly whipped cream, it will result in a mousse with chocolate pieces floating in it as well as a mousse lacking the chocolate flavor.  The chocolate must cool a bit ( 45C° /113F° is the ideal temperature)
   
• Whip 400-gram cold heavy cream and one teaspoon vanilla bean paste to soft peaks, this takes just a few minutes.
   
• Fold the softly whipped cream together with the warm/melted chocolate. Do it as quickly as possible. 
   
• Then fold in the whipped egg vanilla mixture and combine quickly with a spatula.
   
• You will need to use it right away as a filling in the cake as it sets quickly, if it is set too quickly just grab a spatula or big wooden spoon and stir the chocolate mousse for a few minutes. If it is still too stiff to pipe, remove 1 to 2 tablespoons of chocolate mousse and warm it in the microwave until slightly melted. Return the warmed chocolate mousse to the chocolate mousse and mix until smooth.
   
• Fits a pastry bag with an xl large round piping tip. Divide the chocolate mousse into two for the two layers.
   
• Assemble and stack the cake; I use a 20 x 20 cm (8 x 8-inch) squire cake pan to build the cake layers. If you do as I do ( see the step-by-step photos in notes), make sure to cover the inside of the squire pan with plastic wrap, leaving a slight overhang on all sides so that you can easily get the cake/layers out of the baking pan later on.
   
• To assemble, first place a 20 cm (8-inch) preferably chilled cake layer or a 20 cm squire chilled cake layer on a large cake board or cake stand, or do as I do use the square baking pan to build the layers if you use the squire baking pan place your first cake layer in the bottom of the squire baking pan. I prefer to place the cake layer top-side down. This way you'll have a smooth surface to work with.
   
• First pipe a thick ring or a squire "dam of chocolate mousse around the perimeter of your cake, then spoon half of the raspberry cream in the center of the cake, and smooth with the back of a spoon. Top with a second cake layer and gently press down to secure.  
   
• Repeat with the next layer. If the chocolate mousse is set too quickly, just grab a spatula or big wooden spoon and stir the chocolate mousse for a few minutes. If it is still too stiff to pipe, remove 1 to 2 tablespoons of chocolate mousse and warm it in the microwave until slightly melted. Return the warmed chocolate mousse to the chocolate mousse and mix until smooth. If you have some leftover chocolate mousse, place it on top of the raspberry cream.
   
• Top with the third and last cake layer and gently press down to secure. Wrap the cake in plastic wrap. If you don't use a cake pan to build the cake layers, use an adjustable cake ring if you have one and store it in the refrigerator for a few hours or overnight. Bakers tip To get a flat top, place a light book on top of the cake.
   
• Once the cake has been set, take the cake out of the fridge, remove the plastic wrap and place the cake on a turntable or a cake stand. Set aside for now while you make one more recipe of chocolate mousse to coat the cake.
   
• You will need to use the chocolate mousse right away to decorate the cake as it sets quickly. If it is set too quickly just grab a spatula or big wooden spoon and stir the chocolate mousse for a few minutes. If it is still too stiff, remove 1 to 2 tablespoons of chocolate mousse and warm it in the microwave until slightly melted. Return the warmed chocolate mousse to the chocolate mousse and mix until smooth.
   
• Apply the chocolate mousse to the cold cake ( the chocolate mousse gets set very quickly stiff when you apply it to the cold cake), working from the top of the cake down and smoothing with an offset spatula or a straight spatula. 
   
• Chocolate mousse has a lot of air pockets. It won't be as smooth as buttercream, but to get the chocolate mousse to be more smooth on the cake. Put your straight spatula in very hot water for a few minutes. Remove the straight spatula from the hot water, dry it, and use it to smooth out any rough areas on the side and top of the cake use light touch when you go over the cake. Continue with this process until you are pleased with how it looks.
   
• For maximum freshness and delicious serve immediately or store leftovers in an airtight container in the refrigerator for up to 2 days.
   
• Allow the cake to stand at room temperature for at least 1 to 2 hours before serving unless you love eating a slightly cold chocolate cake. If you enjoy the cake slightly cold is has kind of a fudge-like texture.
   
• Want to freeze this cake? after you decorate the cake with chocolate mousse, freeze the cake ( unwrapped for 30 to 60 minutes) after 30 to 60 minutes, then take the cake out of the freezer and wrap the cake with plastic wrap. The night before you want to serve the cake, take the cake out of the freezer, remove the plastic wrap and place the cake in an airtight container in your fridge to come to the right temperature.