Mix flour, baking powder and salt together
Rub in by hand the butter until fine breadcrumbs or use a food processor or stand mixer
Add the sugar and stir
Add the wet ingredients and beat or mix until the dough comes together
Roll out to 2cm deep and chill in fridge for 4hrs or freezer for 1hr
Glaze with equal parts egg yolk and double cream (2 coats)
Hair dryer both coats until dry to touch
Bake at 170C for 13 minutes or until nicely browned on top