Preheat the oven to 350 degrees and spray a 24 mini muffin tin with oil.
Blend oats until they look like fine flour, 1-3 minutes.
Remove oats and set aside. Add the remaining ingredients (except 1/3 apple and walnuts) and blend until smooth.
Add oat flour and blend until smooth.
Stir in remaining chopped apple and walnuts. Pour into mini muffin tin and bake approximately 12 minutes or until a toothpick inserted into the center comes out clean.