Mix together the rolled oats, flours, brown sugar, salt, baking powder, cinnamon. Sieve the flours at least 3-4 times. This adds air to the dry mix.
In a separate bowl add molten butter, and then add in the egg, milk and vanilla extract. Combine these ingredients well with an electric mixer.
Pour the wet ingredients into the dry mixture and add the chopped walnuts and raisins and stir together. Be sure not to over-mix, just gently fold in the batter together.
Now scoop into the muffin tray and bake for about 30 minutes or until a toothpick comes out clean.
Remove from oven, cool on a cooling rack, and enjoy!