Place all the dry ingredients into a large bowl and mix well with your fingers to make sure the rolled oats and brown sugar are evenly mixed through the other ingredients.
1 cup raw chopped, or grated apple
3/4 - 1 cup milk
Melt the butter until liquid than add the egg and 3/4 cup milk, and beat with a fork until mixed. Next grate or chop the apple in a food processor. Press into the cup, removing air bubbles, then stir into the liquids. (Work quickly to prevent the apple from browning.)
Add the apple and liquid mixture to the dry ingredients and mix lightly to dampen the ingredients, adding as much of the extra milk as you need. Coat 12 medium-sized muffin pans with non-stick spray and divide the mixture between them. Bake at 200 C for 12 - 15 minutes or until the muffins spring back when pressed. Leave for 3 - 4 minutes before removing from the pans and cooling on a wire rack.