Preheat the oven to 350 F. Line a muffin pan with paper liners.
In a mug or small bowl, whisk together the chia seeds and water. Set aside for a few minutes to thicken. (can also use a flax egg)
In a large bowl, whisk together the dry ingredients (flour, pumpkin pie spice, baking soda, baking powder, and salt).
In a medium bowl, whisk together the wet ingredients until smooth (chia mixture, pumpkin puree, oil, maple syrup, brown sugar, and molasses).
Add the wet mixture to the dry ingredients and stir until just combined. No patches of flour should remain. Be sure not to overmix. If using, stir in the chopped walnuts.
Divide the batter equally between the 12 muffin liners. They should be about 3/4 full or a bit more. Sprinkle pepita seeds or chopped walnuts on top and gently press down.
Bake the muffins for 20-24 minutes until a toothpick comes out clean. Cool the muffins in the pan for 5-10 minutes, and then transfer each muffin onto a cooling rack until completely cool.
** If using melted coconut oil, make sure that the rest of the wet ingredients are all at room temperature (do not use refrigerated pumpkin, maple syrup, etc. as they will harden the coconut oil).
(Recipe adapted from Oh She Glows)