1. Preheat the oven to 180°C/fan160°C/gas 4.
2. Sift the flour, baking powder and salt into a bowl, then mix in the oatmeal.
3. Rub in the butter until the mixture resembles breadcrumbs.
4. Add 6 tablespoons of cold water, mix to a soft dough and knead until smooth.
5. Roll out on a work surface sprinkled with oatmeal to about 5mm thick, then cut out about 30 circles of dough with a 5cm round cookie cutter.
6. Put on 2 baking sheets and bake for 15 minutes, until just golden. Leave to cool on a wire rack.