Preheat oven to 400 degrees.Add pumpkin puree, coconut oil, and ripe banana to a food processor and process until smooth.Add the eggs to a large bowl and whisk until frothy.Add the pumpkin and banana puree mixture to the bowl with the eggs and whisk until smooth.Add the baking soda, vanilla, pumpkin pie spice, and coconut flour and whisk until smooth.Grease a muffin tin with a dab of coconut oil and fill each tin with the muffin mixture.Sprinkle pecans (if using) over the top.Bake for 13 -15 minutes, or until lightly browned and set in the middle.