Preheat oven to 425 degrees F. In a large bowl, add flour, sugar, salt and baking powder. Stir to combine. In a smaller bowl, whisk together buttermilk, eggs, vanilla and melted butter. Pour liquid into dry mixture and stir until just combined. Set aside.
For the bananas: heat a skillet over medium heat. Add the butter and melt. Add in bananas, maple syrup and brown sugar. Stir gently to coat the bananas. Cook bananas until golden on one side. Flip and cook another minute until golden. Remove from heat.
Spray a half sheet pan (13.5"x17.5") with nonstick spray. Spread pancake batter in the prepared pan. Place bananas evenly over the batter. Scrape any leftover butter/sugar mixture from the bananas randomly over the batter. Bake for 15 minutes, until lightly golden and cooked through.