Ingredients
For the cake
¾ cup + 1 tbsp (120g) all-purpose flour
4 tbsp (30g) unsweetened cocoa powder
1½ tsp baking powder
¼ tsp salt
¾ cup (150g) white granulated sugar
5 egg yolks
5 egg whites
10 tbsp (70g) warm milk
5 tbsp (70g) unsalted butter
For the soft ganache frosting
18oz (500g) heavy cream
13.5oz (375g ) dark chocolate, 50% cocoa solids
2½ tbsp unsweetened cocoa powder
2½ tbsp unsalted butter
Pinch of salt
Method
For the cake
In a bowl, beat the egg whites, with ½ tsp of lemon juice. Once foamy add the sugar one tablespoon at a time and whip egg whites until stiff peaks.
In another bowl mix the egg yolks, melted butter, milk and dry ingredients.
Gently combine both mixtures together without deflating the egg whites.
Spread the mixture in two baking sheets, greased and lined with parchment paper.
Bake the cakes in a preheated oven at 340°F (170°C ) for 10 - 12 minutes or until a toothpick comes out clean.
Allow to cool completely.
For the soft ganache frosting
Bring the cream to a gentle simmer.
Pour the cream over the chocolate, cocoa, butter and salt.
Set aside until it thickens. Depending on the climate you may need to refrigerate the cream.
Tips
The consistency of your ganache will vary depending on how warm/cold the climate is. If your kitchen is really warm (Example: It's summer where you live), you'll need to put it in the refrigerator for it to thicken. Keep an eye on it though or the ganache will set up completely. If this does happen, you can microwave it for 20 seconds until it loosens up again.
Serving
Ideally do not refrigerate this cake. However, if it's summer, or your kitchen is hot, then you can refrigerate it. In that case, take the cake out of the fridge 30 minutes before serving.