Preheat oven to 425℉. Line the bottom of a large sheet pan (about 12”x17”) with parchment paper. Lightly spray the paper and sides of the pan with non-stick cooking spray.
In a large bowl, whisk together the flour, baking powder, sugar, and salt.
In another bowl whisk together the milk, egg, vanilla, butter, and mashed banana.
Create a well in the center of the dry ingredients and add your wet ingredients.
Whisk until just combined, it’s ok if there’s lumps. Do not over mix, you’ll have tough pancakes.
Pour batter onto the sheet pan, spread evenly.
Top the pancake with the slices of banana.
Bake for 20 minutes, or until golden brown, and a toothpick poked into the center of the pancake comes out clean. Slice into 12 squares. Serve immediately with more sliced bananas if desired, caramel sauce, or maple syrup.