Beat the eggs with the powdered sugar until frothy. Mix in the rapeseed oil and egg liqueur and stir with a hand blender to a creamy mass. Mix the flour, cornstarch and baking powder and fold in.
Grease a lamb baking dish with butter and dust with flour, pour in the dough mixture. Bake in a preheated oven at 160 ° C for 30 minutes. Serve dusted with powdered sugar.