Preheat oven to 350°F (175°C). Grease and line two 9-inch round pans.
Beat egg whites with a pinch of salt until stiff peaks form.
In another bowl, whisk egg yolks with sugar until pale and creamy.
Fold in hazelnuts, flour, cocoa powder, then gently fold in egg whites.
Divide batter into pans, smooth tops, and bake 20–25 minutes, until set. Cool completely.
Make chocolate-hazelnut filling:
Heat cream until just simmering, pour over chocolate. Stir until smooth.
Mix in Nutella and butter (if using). Let cool until spreadable.
Assemble:
Slice cake layers in half to make 4 thin layers (optional, for more filling).
Spread chocolate-hazelnut filling between each layer. Frost the outside as well.
Decorate:
Press crushed hazelnuts around the sides, sprinkle cocoa on top, or add chocolate shavings.
Chill & serve:
Refrigerate 2–3 hours (or overnight) for the flavors to meld. Serve slightly chilled.
✨ Tips:
For a lighter Hungarian-style sponge, you can skip flour and make it flourless with only ground hazelnuts.
If you like a coffee kick, add 1 tsp espresso powder to the filling.
This cake stores beautifully in the fridge for up to 4 days.
Ashley, would you like me to also share the Esterházy-style hazelnut variation (with a custard-based filling instead of chocolate ganache)? It’s another Hungarian treasure!
