MASH
Mash your banana in a baking dish.
WHISK
Whisk together the milk, cinnamon, vanilla, and peanut butter if using.
DIP & COAT
Dip bread into the mixture to coat it on both sides.
COOK & FLIP
Heat skillet or griddle and melt butter under medium-low to medium heat. Once it is bubbly, add the soaked bread and cook for 2-3 minutes on each side, until golden brown.