Preheat oven to 200°C Place walnuts on a paper-lined baking tray and toast in the oven for about six to eight minutes. Remove and cool. Sift flour and soda into a large bowl and stir in the sugar. Whisk in the combined milk, egg and butter until batter is smooth. Stir in the banana. Heat extra butter in a frying pan and pour ¼ cup of the batter into the pan, allowing room for spreading, and cook until bubbles appear on the surface of pancake. Turn and cook until browned. Remove from pan and repeat with remaining mixture. Serve pancakes topped with walnuts and icing sugar and drizzled with honey.