Liberally butter a 12-hole muffin tin and preheat the oven to 180C.
Make the topping by putting your chopped 'Bramleys', about one quarter of the finished flesh, in a bowl with the cinnamon, nuts and sugar and set aside.
Make the wet mixture, mixing the sour cream, milk and egg together.
Add the wet to the dry mix, stir well to combine - being careful not to over mix. Spoon the batter into the buttered muffin tin and sprinkle the topping generously over each one. Bake for 25 mins, leave to cool slightly in the tin before removing to a wire rack.
Dissolve your icing sugar with a little drop of water and drizzle over the top when completely cool.