Preheat oven to 350°
Whisk together flour, baking powder, salt & cinnamon in a mixing bowl.
Using a pastry blender, cut in peanut butter and oil until the mixture is pea sized crumbs.
In a separate bowl, beat together mashed bananas, milk and honey.
Add liquid mixture to flour mixture and stir until combined.
Let mixture rest for about 5 minutes. Stir again.
Spoon batter into greased or paper lined muffin cups. I fill these almost completely (less than a 1/4" space) - they will not rise a whole lot.
If using crushed walnuts, sprinkle on tops before baking. If using turbinado sugar, carefully sprinkle tops about halfway thru baking.
Bake for 15 - 18 minutes or until tops are a light golden brown and set.
Remove from tin and cool on wire rack. Enjoy :)