Pour dry ingredients (oatmeal, coconut sugar, baking powder, cinnamon and nutmeg) into the food processor and process on low until it resembles course flour. This should take maybe 1-2 minutes, max.
Add wet ingredients (pumpkin, eggs, vanilla and maple syrup) to the dry ingredients in the food processor. Process on low for another 1-2 minutes until the batter is smooth.
Pour batter into a low-sided greased baking dish.
Bake for 35 minutes at 350°F.
After baking, let cool for a few minutes before cutting and serving.
Notes
If you don't have a food processor, you can make this recipe in the blender. I've made mine in my Vitamix on occasion. It's a bit harder to get the batter out of the blender, but in general, it works well.