Chop chocolate into small pieces and place them into a bowl. Pour pistachio paste on top
Soak gelatin into cold water
Heat 250g cream until simmering, mix gelatin sheet in and pour it over the chocolate & pistachio paste mixture
Let the chocolate cream mixture set for a minute until chocolate gently melts then stir together or hand blend
Once mixture slightly cools to room temp, stir in rest of the cream, cover the top of the ganache with plastic wrap and refrigerate for minimum 4 hours
The mixture should thicken after 4 hours and can be whipped into a pipeable, fluffy consistency in a Stand mixer. Once it is reached a fluffy consistency (1-2min), make sure you do not over whip the ganache as it can break
Whipped ganache should be stored in the fridge before using it or best if you use it immediately
Making the Choux pastry sponge
Pre-heat oven to 180 C / 356 F
Sift flour then measure it and set aside
Place butter, milk, salt and sugar into a saucepan over medium heat
As soon as the mixture starts simmering remove from heat, add the flour in one go and whisk vigorously with a Rubber spatula until it forms one smooth ball and flour bits are not visible
Transfer the dough into a bowl and let it rest for a minute or two before mixing one whole egg in then mix in the egg yolks. Only add a small amount of egg at a time, consistently whisking after each addition. Use either an electric hand mixer or stand mixer
In the meantime beat egg white in a Stand mixer into a a consistency of early stiff peaks but make sure you do not over beat the egg white to a stage where it would form lumps
With the help of a Rubber spatula fold ⅓ of the meringue into the rest of the mixture and mix throughout then fold the rest of the meringue in carefully
Pour cake batter into a 33x33cm Silicone roulade mat or alternatively a large tray, spread cake batter in even and thin layer with the help of an Offset spatula and bake for 20 minutes
Monitor the sponge and take out as soon as it is well baked, avoid over baking as that would results in making it too dry and difficult to fold (=will break)
Let the sponge cool to room temp . Leave it either on the Silicone roulade mat or before assembling flip it over to a parchment paper then flip it again to another parchment so that the top side stays on top
Raspberry coluis
Cook all ingredients in a saucepan over medium heat for 30 minutes or until it thickens. Make sure it gets thick enough so it will be easy to fill it into our cake roll
Chocolate star decoration
Temper Callebaut WhiteChocolate (callets) and spread it over a sheet of parchment paper in a 1-2mm even layer and dust with freezed dried raspberries
At the perfect moment, when chocolate is already hardening but not too hard yet, cut out 5 stars with the help of a cookie cutter. Let the stars further set in the fridge until using them
Assembling
Arrange all the elements: room temp sponge, whipped up ganache, room temp raspberry coulis
With the help of a Offset spatula spread raspberry coulis on top in a thin even layer leaving out 1-2cm around the side
Pipe at least ¾ of the whipped ganache on top of the raspberry coulis and carefully spread it over. Make sure the two cream won´t melt together
Then start rolling the cake tightly and neatly from top to down with the help of a parchment paper or the Silicone roulade mat (that is under the sponge)
Spread the remaining pistachio whipped ganache over and around the sponge and smooth the surface with a piece of parchment paper (see pic above)
Decorate with the chocolate stars and dust with freezed dried raspberry