Preheat your oven to 200°C/180°C(fan)/400°F/Gas 6.
Put 3 Banana in a large bowl and then mash them until smooth.
Add 3 Eggs, 4 tablespoon Maple syrup, 150 g Peanut butter and 1 teaspoon Vanilla extract and stir until all mixed together.
Add 130 g Oat flour, 1.5 teaspoon Baking powder, 1.5 teaspoon Baking soda and 0.5 tablespoon Cinnamon and gently mix.
Slowly stir in 50 g Dark chocolate chips until combined.
Line 9 muffin holes with muffin cases and divide the mixture between them. Put into the oven for 20 minutes, until a toothpick comes out clean.
Notes
Make these muffins even more indulgent by finishing them off with a drizzle of melted dark chocolate. Or even a drizzle of melted peanut butter.
If you like your muffins really sweet, then you can add 3 tablespoon of caster sugar to the mixture, but we don't think it is missing that extra sugar.
If you want to make these without peanut butter, then you can swap it for a runny almond or cashew butter instead. Use a seed butter to make them nut free.
Make sure to fill the muffin cases only ¾ full, as this will give you the nice domed top that muffins should have.