Mix the eggs, powdered sugar and vanillin sugar with a hand mixer with a whisk on the highest setting for 1 minute until frothy. Stir in the oil and Baileys.
Mix the flour with cornstarch and baking powder, sieve and stir in portions on a medium heat. Pour the dough into a greased cup cake tin (Ø 24 cm) sprinkled with flour. Immediately put the tin on the wire rack in the oven.
Top / bottom heat: approx. 180 ° C (preheated), baking time: approx. 60 min.
Let the cake stand in the tin for about 10 minutes, turn it out onto a wire rack and let it cool. Dust the cooled cake with icing sugar.