Mix the rolled oats and yogurt together; add the milk and let the mixture sit for 10-12 minutes.
In a medium bowl, gently mix the flour, sugar, salt, cinnamon, nutmeg, baking soda and baking powder until evenly combined.
In a large bowl, mash the bananas then wisk in the egg and oil. Using a spatula, mix in the oat-yogurt-milk mixture until combined. Gradually add the flour mixture until combined – do not overmix!! If desired, add the carob chips (you could also use chocolate chips, nuts or dried fruit!). Fill the muffin cup about ⅔ of the way full and bake for about 14-16 minutes, or until a toothpick comes out clean! Enjoy!