Crumble the 2 packs of biscuits finely in a deep pot. In a separate bowl, put the milk to boil with 3 tbsp sugar and 4 tbsp cocoa. Let the milk come to a boil, then take off the stove. Pour the boiling milk over the crumbled biscuits. Stir.
Then cover the pot's lid. Stir from time to time. The biscuits need to absorb the liquid. In the meantime, make the cream from 3 egg yolks, 3/4 cup powdered sugar and the butter. Beat with a mixer.
After the biscuits absorb the liquid and cool, mix them with the prepared cream. Stir well. Add 1 cup walnuts and 4 tbsp of the caramelized sugar. Stir well once again. Pour the resulting mixture into a cake form or tray.
Leave them for 24 hours in the fridge. Then make the starch and pour it on top. Sprinkle with walnuts and chocolate sprinkles. You can serve the cake without the starch if you like.