Preheat oven to 350 F, 180 C, gas mark 4. Lightly oil a 7 in (18cm) square cake tin. Melt 85 g butter/marg in a large pan. Remove from heat and stir in 115 g grated cheddar cheese, 1 large egg, eaten, 150 ml natural yoghurt, black pepper and 225 g porridge oats until well blended. Spoon into prepared tin and level the surface. Bake for 30 mins until golden brown. Remove from heat and allow to cool in tin. Cut into 9 squares.
I doubled the ingredients above for the cheesy flaps and used my roasting tin again. Also I cooked on a higher shelf (but not top) and for a bit longer as they were taking ages to brown. Also freezes well, actually tastes better from frozen than fresh.
Thanks to MG who provided me with this recipe.