Preheat your oven to 350 degrees. Spray a muffin pan with nonstick spray or use cupcake liners.
Peel and mash up your bananas in a bowl using a fork. Get them pretty goopy and mash out as many lumps as you can.
Add one egg, mixing it up well before adding the second one and mixing it up too.
Add the milk of your choice and mix well.
Stir in the baking powder, salt, and oats.
Add your blueberries and essential oil or zest.
Add batter to your muffin tin, filling each cup up to the top.
Bake at 350 degrees for 25 minutes.
Remove the pan from the oven and let them cool in the pan for at least 10 minutes, longer if you can.
Once they're cool, run a knife around the edges, then remove them from the pan.