combine the flour, butter and icing sugar in a food processor using a dough hook
blend on a low setting until the butter is mixed in thouroughly
add egg yolks and pulse be patient - and do not be tempted to add water - it will come together!
the mixture will combine to form a ball
relax in fridge while you prepare the filling
roll out on a floured board and line a prepared flan tin butter the sides and bottom well and line the bottom with baking paper. if there are breaks, tears or gaps just press in bits of pastry - no one can see it and it is important that the shell does not leak
bake blind for 15 minutes I have ceramic baking beans and can recommend getting these as it really makes life easier