Preheat the oven to 350°F. Line an 8-inch square baking pan with parchment paper or greased foil. Set aside.
Add the wet ingredients to a large bowl: pumpkin, coconut oil, maple syrup, sugar, flax egg, and vanilla. Whisk until well incorporated.
Add the dry ingredients: oats, oat flour, baking soda, baking powder, cinnamon, cloves, nutmeg and salt. Whisk together until just incorporated, making sure no flour patches remain. Fold in chocolate chips and nuts.
Pour batter into the prepared baking pan. Using a rubber spatula, smooth into an even layer. Optionally, press chocolate chips and nuts into the batter.
Bake for 20-30 minutes, until the edges have browned. Mine took 25 minutes. Allow to cool on a cooling rack for about 1 hour, or until completely cool. Lift out, slice and enjoy! Storing instructions below.