Preheat oven to 350ºF. Place paper muffin liners inside or grease a muffin pan.
In a large bowl, stir together oat flour, flax seed, sea salt, baking powder, cinnamon, ginger, and cardamom. Add pumpkin puree, egg, maple syrup, vanilla extract, egg, applesauce, almond milk, coconut oil and chocolate chips or nuts (if desired). Stir well to incorporate. Allow the mixture to thicken for about 3 minutes before scooping into the muffin pan.
Fill muffin cups almost completely full with batter. Sprinkle with oats and cinnamon. Bake for 23 minutes until the center of each muffin is set. Cool in muffin tin for about 10 minutes so they set and to prevent the muffins from crumbling.
Store in a covered container in the fridge for about a week or freeze for up to 3 months. Label and date containers.