This makes two rounds which fit onto the cold shelf.
Sieve the flour in a mixing bowl.
Add the butter and rub in to resemble breadcrumbs.
Now work the mixture with your hand to bind together to make a smooth dough. When ready cut the mixture in half.
Pat out 2 rounds on the prepared cold shelf.
Pinch the edges to decorate and prick all over with a fork.
For a two oven aga slide the shelf onto the bottom set of runners of the roasting oven.
Bake for 20 minutes.
Remove from the oven and slice each into 8 portions.
Cool on a wire rack and dust with caster sugar.