After trying out some sable biscuit recipes that included nuts and others that included a huge proportion of sugar, I hit upon one (with a bit of tweaking) that seemed to give the right amount of buttery crispness without being too sweet. It doesn't keep long, so I would recommend making the dough to order and storing it in the fridge or freezer un cooked. You then only need to slice off as many biscuits as required and bake them up fresh each time. If you have to make them in advance, store them in an airtight box and crisp them up in a low oven for 10 minutes if they go a little soft. They will still taste great, but crispness is everything with these biscuits.
The font of this new recipe was Jane Grigson - sensible and knowledgeable, I often refer to her when I can't find recipes in fancier books. Her books are great reference works and I would highly recommend the fruit book and vegetable book to add to your library. Anyway, this recipe is based on classic pate sucre (sweet pastry) proportions 1:2:3 - easy to remember! That is to say, 1 part sugar, 2 parts butter and 3 parts flour bound with ice water. Mine goes almost like that, but with some arrowroot and brandy thrown in to increase the 'snap'.
I make this dough in the food processor and it comes together in a matter of minutes. If you want to make it by hand just rub the butter into the flours, stir in the sugar and bind with 1-2 tsp brandy.
In the processor: whizz the flours and icing sugar together for a few seconds to combine and then add the butter and whizz until it resembles fine crumbs. Dribble in 1 tsp of brandy and pulse again - if it looks too dry then add the second tsp. It should come together into a lump quite quickly - don't over process or the biscuits will be tough.
Take the lump out of the processor and form into a rough log on a piece of greaseproof paper. Wrap and roll it into a log about 5cm diameter. Chill for about and hour or over night.
To bake preheat the oven to 160 C (fan assisted) or 180 C without a fan oven. Slice the log thinly (3-5mm) and lay the pieces on a baking trays lined with greaseproof paper. Bake for 10-15 minutes until only just starting to turn pale gold at the edges. If in doubt, take the trays out and cool one to see if it is crisp enough. (Over baking until they are golden brown will affect the taste.) You can always then put them back in again for a few minutes more. Cool on a wire rack.