- For the Joconde biscuit:
- 185g icing sugar
- 185g ground hoursnds
- 50g flour
- 5 whole eggs
- 5 egg whites
- 25 g caster sugar
- 40 g butter For the soaking syrup:
- 20 cl of strong coffee
- 40 g sugar For the chocolate ganache:
- 90g of chocolate
- 108g whipping cream
- 18 g acacia honey For the coffee buttercream:
- 25 g water
- 80g sugar
- ½ vanilla pod
- 100 g egg
- 170 g softened butter
- 10 g instant coffee For the glaze:
- 100g dark chocolate
- 20 g grapeseed oil
- A bit of gold leaf
Preparation 1 hour
Step 1: the chocolate ganache
Melt the chocolate in a bain-marie or in the microwave and bring the cream and acacia honey to a boil.
How to melt chocolate in a bain-marie?
Make an emulsion in 3 times, film in contact and set aside at room temperature.
Step 2: the coffee buttercream
In the bowl of the food processor, whisk the whole eggs.
Meanwhile, heat the water, sugar and vanilla pod seeds over medium heat to 118°C.
Pour the boiling syrup over the eggs and continue whisking until completely cooled.
Then add the softened butter little by little then add the soluble coffee.
Step 3: the Joconde biscuit
Preheat the oven to 230°
To melt the butter.
In the bowl of the stand mixer, beat the whole eggs, the icing sugar, the hoursnd powder and the sifted flour for about 10/12 minutes. The mixture should make the ribbon.
Beat the egg whites with a bird’s beak, incorporating the sugar little by little as soon as they start to foam.
Take ¼ of the first mixture and incorporate the cooled melted butter, then mix again with the egg and powder mixture.
Gently fold in 1/3 of the whipped egg whites then add the rest of the whites without mixing too much to obtain a homogeneous batter. Spread with an angled spatula a layer of 3-4 minutes on the flexipats or on a silicone mat.
Bake quickly for 6-7 minutes a few minutes. The biscuit should be just firm but soft and not too colourful.
Step 4: the soaking syrup
For the syrup, melt the sugar in the hot coffee.
Step 5: the chocolate icing
Temper the chocolate, add the oil, mix well.
Spread the icing on a guitar sheet and let it crystallize for 10/15 min in the freezer.
Step 6: assembly
Cover the icing with a thin layer of coffee cream
Place the Mona Lisa biscuit punched on both sides
Then spread a layer of ganache then again a biscuit punched on both sides, a layer of coffee cream and the last biscuit punched only on the side in contact with the cream.
Place a sheet of baking paper on the cake and block in the freezer for 20-30 minutes
How to successfully bake a cake?
Turn the cake over, unframe it, let it come to temperature without removing the guitar sheet to avoid condensation on the frosting.
When ready to serve, level the sides then decorate with gold leaf.
For this recipe from Mercotte’s Opera, you can count on 60 minutes of preparation. To learn more about the foods in this baked goods recipe, head over to our food guide here.