For the pastry: 150 g butter, 250 g flour (or 250 g gluten free flour and 1 tsp xanthan gum), 2 tbsp icing sugar.
Make the pastry: rub the butter and the flour until the mixture resembles fine breadcrumbs. Add the sugar. Wrap the dough in cling film and chill it for 30 min.
Preheat the oven at 180 C.
Roll the pastry into a tart tin.