Instructions
Preheat your oven to a gentle 170°C (150°C fan) or gas mark 3½. Prepare a shallow baking tin measuring approximately 30 x 22 cm by lining it with baking parchment, ensuring the paper extends up the sides for easy cake removal. Sift the plain flour and cocoa powder together in a bowl, then set this dry mixture aside. In a clean, grease-free bowl, whisk the egg whites until they form stiff, glossy peaks. Gradually add the caster sugar in small increments, continuing to beat until a thick, shiny meringue forms. Next, carefully whisk in each egg yolk one at a time into the meringue, ensuring constant mixing to maintain the batter’s volume and airiness. Gently fold in the sifted flour and cocoa mixture using a spatula, combining everything with light, sweeping motions to preserve the sponge’s light texture. Pour the velvety batter into your prepared tin and bake for about 35 minutes. Once baked, allow it to cool for 5 minutes in the tin before gently lifting it out using the parchment. Re-line the baking tin with fresh parchment to prepare for the next layer. For the meringue layer, whisk the five egg whites until stiff peaks form. Gradually add the caster sugar one tablespoon at a time, whisking until the meringue is glossy and firm. Fold in the finely chopped walnuts, along with the tablespoon of plain flour and potato starch, to bind and add texture. Spread this nutty meringue mixture evenly into your re-lined tin and bake again for 40 minutes on the same oven setting. Once cooked, remove it from the oven and allow it to cool completely. Prepare the luscious chocolate glaze by gently heating the double cream over low heat just until warm. Remove it from the heat, then stir in the chopped chocolate chips, mixing until the chocolate melts fully and the glaze becomes smooth and shiny. To assemble, carefully slice both the cooled chocolate sponge and meringue layers into two equal parts. Place the bottom sponge layer on your serving plate, then top it with a layer of the nut meringue. Sprinkle some reserved chopped walnuts over this layer for an added crunchy surprise. Add the second meringue layer on top, followed by the remaining sponge layer. Finally, pour the glossy chocolate glaze over the top, smoothing it out for a beautiful finish. Decorate the cake with whole or halved walnuts as a charming garnish. Refrigerate the assembled cake for 1 to 2 hours before serving to allow the flavors to meld and the glaze to set perfectly. For best results, slice with a sharp knife warmed in hot water to get clean, neat pieces. Enjoy this elegant Polish treat with your loved ones!
