Preheat oven to 180ºC . Butter an 8or 23 cm square cake pan. In a large mixing bowl, combine the flour, brown sugar, granulated sugar, baking powder, and baking soda. Cut in the butter until the mixture resembles coarse crumbs. Add the nuts. Remove and reserve one third cup of the mixture. In another bowl, beat in the egg, buttermilk, and lemon rind or lemon extract together. Stir the egg mixture into dry ingredients. Do not overmix. Batter will not be smooth-looking. Turn batter into prepared cake pan. Sprinkle reserved crumb mixture over the top. Bake 25 minutes, until golden. Serve warm. makes 1 8 inch or 23 cm square cake Recipe