Ingredients for cake:
10 oz. butter (unsalted)
10 oz. sugar
9 eggs, separated
10 oz. semisweet chocolate, shaved on box grater or using grater attachment of food processor
10 oz (2 ¾ cups) almond meal (also called almond flour)
Ingredients for ganache (this made about 1 ½ cups more than I needed):
1 ½ pounds semisweet chocolate, finely chopped
3 cups heavy cream
4 TBSP butter
2 TBSP espresso powder
Butter for greasing pan
Berries, nuts or other décor for serving
Preheat oven to 350 degrees. Grease a half-sheet baking pan (13x18 inch) with butter and line with parchment paper.
Cream butter, sugar and egg yolks together in stand mixer with paddle blade on medium until light and fluffy, about 3 minutes.
Add shaved chocolate and almond meal and mix on low until well distributed, then turn up to medium and mix for an additional minute.
In a separate mixing bowl, whip the egg whites on medium to form soft peaks (about 3-4 minutes). Slowly and gently mix the egg whites in to the batter, 1/3 at a time, until all incorporated.
Pour batter into prepared pan and bake for 25 minutes or until tester comes out clean.
Remove from oven and cool in pan completely.
Cover a cutting board with parchment and invert the cake out on to the board. Remove the parchment from what is now the top of the cake.
Make ganache by bringing the cream and espresso powder to a gentle simmer then pouring it over the finely chopped chocolate. Gently stir every few minutes until fully smooth. Allow ganache to cool for 15 minutes.
When cooled, pour 1/3 of ganache over cake and spread out evenly (don’t make it too thick). Place cake in fridge to cool completely.
Cut cake into thirds (across the narrower dimension, not the longer) and stack carefully. Trim any ragged edges, then cut cake in half (again, across the narrower dimension). Stack the two pieces to make a cube and trim again if needed.
Drizzle and spread the ganache over the 4 sides of the cube-this is a bit messy, but just go with it. Refrigerate, carefully covered, until about 20 minutes before serving.
Decorate with berries/nuts or flowers as desired.