Pre-heat the oven to 350℉.
Peel and grate the apple. Peel and finely dice the pears. Add all wet ingredients to a medium bowl. Stir to combine.
In a separate medium-large bowl, add the dry ingredients together.
Add the wet ingredients to the dry ingredients and stir to combine.
If you are making the crumble, grind up half of the oats (so you should have ¼ cup ground up oats, ¼ whole oats).
Mix the oats with the maple syrup, melted butter or oil, and cinnamon. Stir to combine.
Sprinkle the crumble on top of the muffins in a small layer.
Bake in the oven at 350℉ for 15-18 minutes.