Prepare the pudding with 600 ml instead of the 500 ml milk indicated on the package, so that it becomes runny. Remove the pudding from the hob, let it cool down briefly, add the bottle of egg liqueur. Mix in 1-2 shots of rum depending on your taste (be careful, rum is extremely tasty). Season with vanilla sugar.
If necessary, fill eggnog in cups or glasses and garnish with icing.
I like it much better than eggnog with white wine and is also much creamier. Can also be seasoned with cinnamon or - then make it thicker - served as a drunk vanilla sauce.