Preheat oven to 180°C and line a 9-inch loaf tin with baking paper.
In a large bowl, combine all wet ingredients together and mix well. Sift in flour, salt and cayenne pepper and mix until just combined. Fold in walnuts, taking care not to over mix.
Pour batter into prepared loaf tin and bake for 55-60 minutes, or until cooked through.
Allow to cool in loaf tin for 10 minutes before cooling further on a wire rack.