..... made from leftover shortcrust pastry.
The first time I made these, I think I misunderstood the recipe, as they were far too sweet to be eaten as savoury biscuits; with a reduced amount of sugar the second time, they were just right for me, but the sugar could be reduced even further. Alternatively, with more sugar and perhaps some spices for flavouring, these would make a tasty sweet biscuit too! The baking time suggested was 10-12 minutes but a bit longer gives a crisper biscuit - just don't let the biscuits colour too much!
First weigh the pastry scraps. In a bowl, add the same weight of rolled oats and half that weight of butter. Leave for a few minutes for the butter and pastry to soften a little. Add sugar equal to a quarter of the weight of the original pastry scraps (or less, to taste). Knead everything together by hand or in a food processor to give a uniform dough. On a floured board, roll out the dough to about 5mm thickness, cut into 8cm rounds (or whatever shape you like - fingers or squares would be simpler) and put on a baking tray lined with parchment. Re-roll any scraps and repeat until the dough is all used. Bake at 180C until the biscuits are firm and lightly coloured (10 minutes plus!), then cool on a wire rack.
I had 150g of leftover pastry, and made over a dozen biscuits from this recipe. There are other good ideas for using up pastry scraps on this link to the Guardian article.