Preheat the oven to 350F/180C.
Mash one banana and whisk with the egg, yogurt and coconut oil.
Add the vanilla and baking powder.
Add the oats and chop ½ banana in chunks - add these to the mixtures too. Let sit for 5 minutes (optional).
Pour the batter into silicone muffin cups and top with a slice of banana (optional).
Bake the muffins for 20-30 minutes, checking on them every now and then. The muffins are done when they're nicely brown and a toothpick comes out clean when you punch them with it.
Let cool off and enjoy!
