This recipe is an invention of my own. I combined two famous European desserts: sachertorte and semifreddo.

Sachertorte is a chocolate cake of Austrian origin, invented by Franz Sacher, supposedly in 1832 for Prince Metternich in Vienna. It is one of the most famous Viennese culinary specialties. A key characteristic of sachertorte is a layer of apricot jam in the middle.

Semifreddo is a class of Italian semi-frozen desserts. It has the texture of frozen mousse. Semifreddo is often called "Italian ice-cream cake".

My dessert consists of layers of frozen chocolate mousse, with layers of dense, frozen chocolate cake, and a layer of apricot jam. It is topped off with a chocolate ganache drizzle.

I made this with unsweetened chocolate. It is not an overly sweet dessert, it has a very strong, almost bitter, dark chocolate flavour. It can be made sweeter by substituting semi-sweet chocolate.

Supplies

Cake:

52 g (2 oz) unsweetened, baking chocolate*

1/2 tsp vanilla extract

60 g (4 tbsp) softened, unsalted butter

80 g (10 tbsp) powdered sugar (divided)

2 extra-large eggs

56 g (6 tbsp) whole wheat flour*

80 g (4 tbsp) apricot jam

Mousse:

4 extra-large eggs

125 g (4.5 oz) unsweetened, baking chocolate*

10 g (2 tsp) unsalted butter

125 ml (1/2 cup) heavy cream*

35g (4 1/2 tbsp) powdered sugar

Ganache:

85 g (3 oz) semi-sweet, baking chocolate

90 ml (6 tbsp) heavy cream

Notes:

*We measured our ingredients using the metric system. The measurements in brackets are only an approximation. If you have a scale, this is the time to use it.

*We used unsweetened baking chocolate. The cake was not overly sweet. If you prefer it to be sweeter, use semi-sweet, baking chocolate.

*Whole wheat flour will give the cake it's signature, dense, texture. If you prefer a lighter, fluffier cake, or don't have whole wheat flour, substitute all-purpose flour.

Step 1: Cake

Preheat your oven to 340°F (170°C). Line a 21 cm x 11 cm x 6 cm (8 1/2 in. x 4 1/2 in. x 2 1/2 in.) baking pan with baking paper, grease the sides, and dust with a little flour. Melt chocolate in the microwave, stopping and stirring every thirty seconds until melted. Let cool slightly.
Using a hand mixer with whisks, beat the softened butter with the icing sugar and vanilla extract until bubbles appear.
Separate the eggs. Whisk the egg yolks into the butter mixture one by one. Now gradually add melted chocolate. Beat the egg whites with 40g (5 tbsp) of the icing sugar until stiff, then place on top of the butter and chocolate mixture. Sift the flour over the mixture, then fold in the flour and beaten egg whites.
Transfer the mixture to the springform, smooth the top, and bake in the oven (middle rack) for 10–15 minutes, leaving the oven door a finger's width ajar. Then close the oven and bake for approximately 20 minutes. (The cake is done when it yields slightly to the touch.)
Remove the cake from the oven and loosen the sides of the springform. Carefully tip the cake onto a cake rack lined with baking paper and let cool for approximately 20 minutes. Then pull off the baking paper, turn the cake over, and leave on a rack to cool completely.
Cut the top of the cake off so you have a flat top. Cut the cake in half horizontally.
Take the pieces you cut off and crumble them. Reserve them for later.

Step 2: Mousse

Separate eggs and yolks while eggs are cold. Place whites in a large bowl and yolks in a small bowl. Leave whites while you prepare other ingredients.
Whisk yolks.
Place chocolate and butter in a bowl. Melt in the microwave in 30-second bursts, stirring in between, until smooth. Set aside to cool - proceed with other steps.
Beat cream until stiff peaks form
Add sugar. Beat whites until firm peaks form.
Fold egg yolks into the cream using a rubber spatula. Streaks are ok.
Touch the chocolate. It should still be runny but only lukewarm. If it's too thick, microwave 2 x 3 seconds until runny.
Pour chocolate into cream yolk mixture. Fold through. Streaks are ok.
Add 1/4 of beaten egg whites into chocolate mixture. Fold through until incorporated.
Pour chocolate mixture into egg whites. Fold through until incorporated and no more white lumps remain.

Note :

When incorporating your ingredients, try not to over-mix. If you mix too much, you risk deflating your eggwhites and cream.

Step 3: Assembly

Line the same pan you baked your cake in with plastic wrap/cling film.
Spread half the mousse on the bottom of the pan.
Place a piece of cake on top of the mousse. Press the cake into the mousse so the mousse covers the sides of the cake
Next, take the apricot jam and heat it in the microwave for 30 seconds.
Spread the apricot jam onto the cake layer.
Place the second layer of cake on top of the apricot jam.
Finally, spread the rest of the mousse on top of the cake. Try to get it to cover the sides of the cake slices.
Smooth out the top and place in the freezer for at least 4 hours, preferably overnight.