Keto Opera Cake

Butter, Milk, Egg yolk, Erythritol, Water, Gelatin, Coffee, 85% chocolate, Cream, Erythritol, Butter, Egg, Egg white, Almond flour, Erythritol, Allulose, Lupin flour, Baking powder without starch, Cooking salt, Cream, 85% chocolate

Let it stand: 25 min. Heat on the stove: 10 min. Whisk with a mixer: 10 min. Cool down: 30 min. Blend with a blender: 5 min. Chill in the refrigerator: 4 h. Mix: 10 min. Whisk with a mixer: 15 min. Bake in the oven: 20 min. Cool down: 20 min. Cooking: 20 min. Chill in the refrigerator: 10 h. Mix: 10 min. Chill in the refrigerator: 1 h.

Preparation of Coffee Cream

Soak gelatin (5 g) in water (20 g) for 20-30 minutes.

In a saucepan, combine milk (80 g), erythritol (70 g), instant coffee (4 g), and the swollen gelatin. Heat almost to boiling and immediately remove from heat.

The amount of erythritol is calculated for a regular sweetener 1:1 to sugar. If using a sweeter concentrated sweetener, reduce the amount to taste.

Whisk the egg yolks (80 g) until light and fluffy. Gradually pour in the hot milk mixture while constantly whisking. Pour the mixture back into the saucepan and heat over low heat, stirring, until slightly thickened and the temperature is about 75 °C.

Cool the custard to 40 °C. Add softened butter (170 g) and blend with an immersion blender until smooth. Cover with plastic wrap directly on the surface and refrigerate for 3-5 hours until the cream thickens.

Preparation of Ganache

Heat 35% cream (70 g) with erythritol (30 g) almost to boiling. Pour the hot cream over 85% chocolate (80 g), stir, add butter (10 g), and blend until homogeneous.

Cover the ganache with plastic wrap directly on the surface and cool for 2-3 hours until it reaches a thick but pliable texture. If the ganache becomes too thick, take it out of the refrigerator in advance and let it warm slightly at room temperature.

Preparation of Biscuit

Preheat the oven to 160 °C in top-bottom mode without convection. Mix almond flour (55 g), lupin flour (5 g), and starch-free baking powder (4 g).

In a separate bowl, mix half of the allulose (20 g), erythritol (25 g), salt (1 g), and citric acid if using.

Whisk the egg white (120 g) until soft peaks form, gradually adding the sweet mixture. In another bowl, whisk the egg (150 g) with the remaining allulose until it whitens and increases in volume. Fold in the dry mixture, then gently combine the batter with the whipped egg whites.

Spread the batter on a silicone-lined parchment paper in a rectangle about 37×32 cm. Bake for 15-20 minutes until lightly golden. Remove the parchment from the warm biscuit, let it cool completely, and cut the layer into 3 equal cakes.

If you want a clearer bottom layer, brush one cooled cake with a thin layer of melted chocolate and chill until set. When assembling, place this cake chocolate side down.

Cake Assembly

Place the first cake layer on a work surface. Spread half of the coffee cream, cover with the second cake layer, and spread all the ganache.

Place the third cake layer, spread the remaining coffee cream, cover with plastic wrap directly on the surface, and refrigerate for 10 hours for stabilization.

Preparation of Chocolate Glaze

Heat 35% cream (60 g) with erythritol to taste if you want a sweeter coating. Pour the cream over 85% chocolate (40 g) and mix until smooth. If the mixture is too thick, add softened butter in small portions.

Pour the glaze over the stabilized cake, smooth it out, and refrigerate for at least 1 hour. Store the cake in a closed container in the refrigerator for up to 72 hours.