Sift the pastry flour.
Split the vanilla pod lengthwise with a knife and scrape out the seeds with the help of a teaspoon.
In a separate large bowl, mix together the eggs, the milk, the sugar, the salt and the vanilla seeds with an emulsion blender until smooth.
Add the pastry flour and the melted butter and mix again.
Cover the bowl with a cling film and put in the fridge for approx. 20 minutes