Preheat oven to 200ºC / gas 6
Line an ANTA baking dish with damp greaseproof paper which helps shape the paper to the dish, and heat the dish in the oven.
Finely chop the walnuts and chop the cheese into small cubes.
Sieve the flour and baking powder into a large bowl.
Cube the butter and rub into the flour until it resembles breadcrumbs.
Add the walnuts and cheese.
Whisk the milk and yoghurt together and add to the flour, bringing together with two knives in a cutting motion.
Remove baking dish from the oven.
On a floured surface, shape the dough to the size of the baking dish and carefully place in the paper case shell.
Bake for 12-15 minutes until golden brown.
Allow to cool in the baking dish for about 15 minutes and then lift out onto a wire rack to cool.
Beware the baking dish may still be very hot.