In a food processor or in a plastic bag and using a rolling pin, crush the pretzels until you have a fine, sandy mixture
Whisk together the butter and icing sugar until light and fluffy
whisk in the vanillas
stir in the crushed pretzels, salt and flour, plus the milk. Add 1 tsp milk to start and if the mixture is too dry add the second tsp
Once you have a nice dough, wrap and place in the fridge for half an hour
Preheat the oven to 190℃ and line a baking sheet with parchment
Roll the dough into ten even sized pieces and place onto the baking sheet
Bake for 16 minutes, or until the bottoms have started to turn golden
Meanwhile, sift the 4 tbsp icing sugar into a shallow bowl.
As soon as the cookies come out of the oven roll in the sugar and place back onto the hot baking sheet for the sugar to crisp up
Once they've cooled a little, roll them for a second time in the sugar then place onto a wire rack to cool fully.
