Mix flour, powdered sugar, salt, vanilla sugar, and baking powder.
Crumble the butter into the flour mixture and quickly gather the dough with the cold water.
Wrap the dough in plastic and let it rest in the fridge for about 40 minutes.
Take the dough out of the fridge, divide it in two, and roll out two long rectangles of about 10 x 30 cm.
Trim the edges so both rectangles are the same size.
Bake the bases for about 11-13 minutes at 200 degrees Celsius (392 degrees Fahrenheit) (conventional oven) until the edges are golden.
They should not be hard like cookies.
Take out the bases, let them cool slightly, and spread a layer of raspberry jam on one base.
Place the other base on top, make a good thick icing, spread it on, and sprinkle with sprinkles before cutting the slices with a sharp knife.
Enjoy!