Combine the sugar, orange zest & invert sugar.
Whisk together the whole eggs & heavy cream. Once whisked, mix in the sugar mixture.
Sift together the cocoa powder, pastry flour & baking powder. Once sifted, add to the mixture.
Combine the butter, oil & 811 callets, and melt to 35°C. Slowly add to the batter, and leave to rest overnight in the fridge.