Preheat the oven to 180C.
Melt the coconut oil in the microwave (about 30 seconds) or in a bowl over a pan of water, it won't take long. Leave the coconut oil until just warm to the touch.
Line one muffin tin with 12 paper liners.
Sieve the flour, coconut flour (or cornflour), baking powder and bicarbonate of soda and salt into a large baking bowl. Add the rolled oats and sugar and stir to mix.
Mash two of the bananas in a bowl and dice the other
In a smaller bowl mash two of the bananas, mix in the eggs, yogurt and vanilla extract.
Mix the coconut oil into the dry ingredients until well combined, then gently add the banana and egg mixture and stir.
With a metal spoon gently fold in the diced banana, 40g of nuts and 40g of the chocolate.
Divide the mixture between the 12 paper cases and sprinkle the tops with a mixture of the remaining, chocolate, nuts and the coconut chips.
Bake for 20-25 minutes.
Leave the muffins in the pan for about 10 minutes before removing to a cooling tray. Cool completely before eating...if you can wait!