Let’s give the floor to the pastry chef: “I’m offering you the "Prague cake" recipe with my personal additions. The cake will be 18 cm (7 inch) in diameter, and with a height of about 15 cm (5.9 inch). The amount of the ingredients can be reduced by 1.5 times, so you will get a lower cake. The cake is very stable, and it doesn’t fall apart; but cutting it into small portions will not be easy.”
Chocolate sponge biscuit
For the chocolate biscuit (the calculation is for 2 biscuit layers with a diameter of 16 cm | 6.3 inch):
- Egg 105 g | 3.70 oz
- Sugar 80 g | 2.80 oz
- Almond flour 30 g | 1.05 0z
- Flour 50 g | 1.75 oz
- Cocoa powder 10 g | 0.35 oz
- Baking powder 4 g | 0.15 oz
- Cream 50 g | 1.75 oz
- Bitter chocolate 30 g | 1.05 oz
- Butter 40 g | 1.40 oz
Heat and mix the chocolate, the butter and the cream. Mix all the dry ingredients, and combine both mixtures; add the eggs. Bake the biscuits at 180C (356F) for 25 minutes until dry toothpick. Remove the cakes from the oven, and cool them completely. Remove them from the molds, then wrap in foil, and place in the fridge overnight.
For the apricot filling:
- Apricot puree 100 g (wash apricots, remove pits, boil until soft, and mush with a blender; rub through a fine sieve) | 3.55 oz
- Apricots cubes 200 g | 7.05 oz
- Sugar 70 g (optional) | 2.45 oz
- Pectin 5 g | 0.20 oz
- Lemon acid 3 g (diluted with the water 1:1) | 0.10 oz
- Tarragon to taste | 0.00 to taste
Bring the apricot puree with the tarragon to a boil (finely chop the tarragon). Cover it with a lid and let it brew for 30 minutes. Add the diced apricots to the puree, and heat it to 45C (113F); add the sugar, mixed with the pectin, and boil for 2 to 3 minutes; remove from the heat, add the lemon acid, and mix. Pour the filling into a 16cm (6.3 inch) mold and freeze.
For the chocolate ganache:
- Bitter chocolate (you can take the milk one) 115 g | 4.05 oz
- Cream 33% 135 g | 4.75 oz
- Butter 45 g | 1.60 oz
- Apricot brandy or liquor 45 g | 1.60 oz
Bring the cream to a boil, and pour it over the chocolate; cool the mixture to 40C (104F) and add the butter, mush it with a blender. Add the apricot liquor and mush it once again. Place the ganache on the frozen apricot filling, and freeze.
For the apricot-tarragon custard:
- Apricot puree 150 g | 5.30 oz
- Butter 50 g | 1.75 oz
- Yolks 60 g | 2.10 oz
- Gelatin 4 g | 0.15 oz
- Sugar 45 g | 1.60 oz
- Tarragon to taste | 0.00 to taste
Soak the gelatin in 24 g (0.85 oz) of water. Mix the yolks with the sugar. Bring the puree with the chopped tarragon to a boil, and gently pour it over the yolks in parts, carefully stirring with a whisk. Place the resulting mixture on a low heat (better in a water bath) and boil until 83C (181F), stirring. Remove the mix from the fire, and gently add the swollen gelatin; mix. Cool the custard to 30C (86F), add the butter, and gently mush it with a blender. Pour the custard into the 16 cm (6.3 inch) ring mold, and freeze it. You can also pour the custard into silicone spheres.
For the chocolate mousse:
- Milk 323 g | 11.40 oz
- Bitter chocolate 350 g | 12.35 oz
- Milk chocolate 100 g | 3.55 oz
- Gelatin 14 g | 0.50 oz
- Cream 33% 647 g | 22.80 oz
Heat the milk, and dissolve the gelatin in it; melt the chocolate in the microwave, and pour the milk with the gelatin onto the chocolate. Mush the mass with a blender until an emulsion is obtained. Whisk the cream separately until soft peaks, and add it to the chocolate mass, then stir.
First, cut the biscuit horizontally into two cakes.
Tighten the ring mold with a diameter of 18cm (7 inch) with foil.
Pour out some mousse, then place a layer of the custard (or lay out the custard balls, and pour the mousse over them).
Cover it with the cake, and follow the next order:
- apricot center and ganache
- a little mousse
- another cake
Pour the mousse over the final cake.
Place the cake in the fridge overnight.
Cover the ice cold cake with the glaze or the chocolate velours.
I also added a crunchy layer to the cake. You can place it inside or refuse it at all.
For the crispy layer:
- Chopped and roasted walnuts 20 g | 0.70 oz
- Crispy apricots 5 g | 0.20 oz
- Milk chocolate 40 g | 1.40 oz
- Olive oil 15 g | 0.55 oz
*To make the crispy apricots, slice them thinly, and dry them in the oven at 65-80C (149 to 176F) for several hours.
Melt the chocolate and mix it with the vegetable oil. Add the nuts and the apricot chips. Spread a thin layer over the biscuit, and freeze.
For the chocolate crumble:
- Butter 100 g | 3.55 oz
- Sugar 100 g | 3.55 oz
- Coarse salt 3 g | 0.10 oz
- Almond flour 100 g | 3.55 oz
- Flour 87 g | 3.05 oz
- Cocoa 7 g | 0.25 oz
Whisk all the ingredients with a mixer or chop them with a knife until smooth crumbs. It is important to ensure the minimal contact of the dough with the hand warmth. Pour the crumb layer evenly on a baking sheet, and bake at 180C (356F) for 12 to 15 minutes. At this time, heat another 100 g (3.55 oz) of butter to 150C (302F), and strain it through a very fine sieve. Cool the baked crumbs, and mix them with the ghee (to taste).
Use the mass to form the bottom and the sides for the Prague cake. Send the “mold” to the fridge for 30 to 60 minutes. You can put a crispy layer on the bottom or just place the cake in it.