Grind 1.5 cups of oats in a food processor until they are almost flour consistency. Mix the bananas is a mixer until they are almost liquid and then add the other wet ingredients. Add the dry ingredients (except chocolate chips) to the wet ingredients and mix well. Allow to sit for 10 minutes and then stir in half of the chocolate chips.
I did not like using liners, maybe you have better luck than me. I tried them once and now just use the tins without liners. I have also made these with and without the oats on top... the oats add visual interest but the muffins are just as delicious without them!