Obvious isn't it? Forget everything you’ve heard about keeping pastry cool, putting it in the fridge and leaving to rest. That applies to mixtures with gluten and this hasn’t got any gluten.
The best I've made was using the standard proportions, 4oz gluten free flour, 2 oz butter and 2 tablespoons water (sorry I still use ounces). Butter best if at room temperature, not cold from the fridge.
Rub together flour and butter then add water, then squeeze it all together by hand, working in the last crumbs of dry mix - DON'T be tempted to add extra water.
You can use it straight away, but I find it’s better if it’s left overnight, still at room temperature, wrapped in cling film. Maybe this gives time for the grains to soften. This works just like regular pastry; no need to roll out between sheets of cling film.
I made a large batch using 500gm flour, 250gm pack of butter and 8 tbsp water - I also added about a level tsp gluten free baking powder and ½ tsp salt, but doubt it made much difference. This produced a crisp pastry (for mince pies) which didn't fall apart.
I find that gluten free pastry doesn't brown like normal pastry. With leftover pastry - add handfuls of grated cheese to taste - roll out thickly and cut into strips to make cheesy biscuits / cheese straws.
With so many of us gluten free I thought I would post this here.