Flourless Chocolate Cake

• 1 Package (250g) unsalted butter
• 1 ½ Package (300g) chopped dark chocolate (couverture)
• 3 Tablespoons espresso coffee or 1 tablespoon instant coffee dissolved in 2 tablespoons hot water
• 6 Eggs, yolks and whites separated
• 3/4 Cup (170g) granulated sugar
• 1 Cup (100g) soft light brown sugar
• 1 Tablespoon (10g) vanilla extract
• 3 Tablespoons (30g) cocoa powder

For serving

• Raspberries and blueberries

1. Preheat the oven to 160°C. Butter a 23 cm springform pan and line the base with parchment paper.
2. In a glass bowl, place the butter and chocolate and melt them over a double boiler (bain-marie). That is, place the bowl over a saucepan of water. Be careful, the bottom of the bowl must not touch the water. Heat until the chocolate melts. Add the coffee to the chocolate and stir.
3. Place the egg whites in a mixer and beat until you have stiff peaks (a firm meringue). Transfer this to a bowl. Put the yolks, both types of sugar, and vanilla into the mixer bowl. Beat for 5 minutes until the yolks lighten and the mixture becomes fluffy.
4. Add the sifted cocoa powder and the cooled chocolate mixture. Lower the mixer bowl and gently fold in the meringue using a spatula with circular motions.
5. Pour the mixture into the pan and bake in the preheated oven for 70 minutes. To check if it's done, insert a wooden skewer into the center of the cake; if it comes out clean, then remove it from the oven. Let it cool and garnish with the raspberries and blueberries.