Mix the eggs, sugar and vanilla sugar with the whisk of the hand mixer on the highest setting for 1 minute until foamy. Stir in the oil. Mix the flour with the cornstarch and baking powder, sift and stir in portions on a medium heat. Divide the part into 2/3 and 1/3.
Stir into the 2/3 batter of Bailey`s. Add the ground hazelnuts and stir in as well. Stir the marzipan mixture into the 1/3 batter, add a little milk if necessary.
Grease the oven`s drip pan well and preheat the oven to 190 degrees bottom / top heat. Spread the Baileys mixture on the drip pan. Spread the marzipan mixture over it. Do not stir in. Bake in the oven for 20-25 minutes.
Then let cool down a little in the drip pan. Dust with powdered sugar and decorate with melted chocolate or couverture. Cut into pieces on the baking sheet.