Photograph: Jan Baldwin
To make the biscuits, put both types of flour, the butter, sugar, baking powder and a large pinch of salt in a food processor and pulse briefly. Add the milk and pulse until the mixture begins to come together. Transfer to a bowl, add the oats and, using your hands, knead until the oats are mixed in.
Shape the dough into a disc, wrap in clingfilm and chill for at least 1 hour.
Preheat the oven to 180°C, fan 160°C, gas 4. Remove the dough from the fridge and set it aside for 10 minutes. Roll out the dough on a lightly floured surface to 5mm thick – it will be short and crumbly, so persevere.
Cut out 20 circles from the dough using a 4cm round cutter. Bake on a lightly greased baking tray for 15 minutes. Cool on wire racks.
For the creamy blue cheese, remove both cheeses from the fridge at least 30 minutes before using. Blend all the ingredients, except the cress, in a food processor until combined. Pipe or spoon the cheese on to the biscuits and top with the cress.
Get ahead: make the oatcakes up to a week ahead. Once cool, transfer to an airtight container. They can also be frozen. Make the cheese mixture up to 2 days ahead
Kitchen secret: if you don't have time to make the biscuits, simply serve this as a dip for crudités or nachos.