Line a loaf pan (30 cm) with baking paper. Melt the butter and 100 g nougat separately. Beat the eggs and powdered sugar with the hand mixer for about 8 minutes, then fold in the egg liqueur and butter. Briefly fold in the sifted flour-starch-baking powder mixture with the whisk.
Halve the dough. Mix the melted nougat and cocoa into one half. Put the dough into the loaf pan in alternating layers of tablespoonfuls, not smoothing the dough portions out, but placing them in the center of the pan so that they are pressed outwards by the next layer. Bake at 180 degrees for about 60 minutes (stick test). Let cool down.
Melt the rest of the nougat and cover the cake with it. Scrape shavings from a white couverture block with a peeler and decorate the cake with them.