Chop the flour and butter together, pour in the beer and quickly knead everything into a dough. Chill for at least 30 minutes (better longer). Dough without sugar!
Halve the dough. Grease 2 trays (36cm x 32cm) and roll out the dough evenly, prick several times with a cake fork. Bake in the preheated oven at 175 ° for about 20 minutes. Let cool down.
For the cream, bring 3/4 liter of milk with butter to the boil, add sugar. Mix the rest of the milk, eggs, flour, custard powder and vanilla sugar together. Pour into the boiling milk, stirring constantly until the pudding is thick.
Place it on top of one sheet of dough while it is still hot and cover with the second sheet, let cool.