Preheat oven to 200°C.
Sift whole-wheat flour, baking powder, maize flour and cinnamon together.
Add the remaining wheat left in sieve to mixture.
Beat egg, oil and sugar together and mix into dry ingredients.
Dissolve the bicarbonate of soda in the milk and add with the banana and dates to the flour mixture.
Mix until flour is just moist and batter is still lumpy.
Do not over mix.
Spoon batter into a greased muffin pan and bake for 20 minutes.
Allow to cool in pan before turning out onto a wire rack.
Serve warm with butter.