Preheat oven to 350 degrees F. Line or spray 12 muffin tins.
Take 1 cup of the old fashioned oats and pour into a blender or food processor. Pulse the oats for 30 seconds or until you they resemble a thick flour that resembles corn flour. Don’t over pulse or you will get a sticky flour. You can also use 1 cup of pre-made oat flour instead of grinding your own.
In a large bowl, whisk together the oats, oat flour, baking powder, cinnamon and salt.
In a medium bowl, whisk together the smashed bananas, eggs, milk, syrup, coconut oil and vanilla extract.
Pour the wet ingredients into the dry ingredients and stir until incorporated.
Gently stir in add-ins.
Spoon oat batter into the muffins tins all the way to the top.
Bake for 30 minutes or until just golden brown on top. Let cool slightly and serve.