Even if you are not on a gluten free diet this pastry is really worth making - with the potato in it crisps up and the rice flour adds a great flavour too. It's quite like parmesan shortbread. Next time I make it I'm going to add parmesan too. It's not for the faint hearted though - it can be quite breakable. But the good thing about it is because there is no gluten content it doen't really shrink when cooking, so you can cut it out to the size of your baking tin, and any holes you patch up will stay patched up as it cooks.
I remember the first time I used this recipe and didn't use the xanthan gum - I had a few kitchen nightmares that day. You really need the xanthan gum for this to help it glue together.
There's more about the St. Agnes tart in a previous post.
Unlike normal bread this is quite a moist mix (500g of flour to 420ml water) so it is mixed in the electric mixer rather than by hand kneading.
A third rice flour, a third tapioca flour and a third potato flour for these and a couple of teaspoons of xanthan gum (which replaces the effect of the gluten), 7g intant dried yeast and 1 tsp salt, sugar and baking powder.
I mixed in the walnuts, raisins and rosemary after this and left it to prove before rolling out. To roll out you need to flour your hands really well with rice flour as the dough is very soft. Remember to use rice flour as well to sprinkle on the tray to stop them sticking - easy to use normal flour out of habit, and then you have to start again.
They came out really smooth which is amazing for gluten free bread and tasting great with all those ingredients. If you are going to keep them they start to go hard even if kept in an airproof container so you just need to 'refresh' them in the oven, microwave or by toasting them before eating them.
I used the same rice/ tapioca/ potato flour mix in place of normal flour in my blinis recipe and added a couple of teaspoons of xanthan gum as well. Again, the different tastes of the flours was really good.