Preheat the oven at 180 Deg C.
Grease or line a muffin tin with muffin cases.
In a large bowl whisk in the dry ingredients except oats.
Add in the oats to the dry mix and give a quick mix.
In a food processor finely process the butternut squash and apple until it resembles a puree.
Add this puree into another bowl.
Add in the egg, vanilla extract, maple syrup, butter and give everything a nice whisk so that the egg is well incorporated.
Now add the dry ingredients to wet and mix everything.
Do not over mix. Mix until all the ingredients are well incorporated. Be sure to mix it right till the bottom of the pan.
Fill in the muffin tray with batter.
If using chocolate chips/chunks add them on the top.
Bake in a preheated oven for 18-20 minutes.
It's done when a toothpick inserted comes out clean.