In a medium bowl, whisk together the flour, sugar, baking powder, and salt.
In a large bowl, mash the bananas with a fork until only small chunks remain. Add the milk, eggs, vanilla, and oil, and mix until combined.
Pour the dry ingredients into the wet ingredients, and mix until just combined (a few small lumps are fine). Let sit 5 minutes.
While the batter is resting, preheat a skillet or griddle over medium heat. Spoon the pancake batter onto the hot griddle by ¼ cup scoops. Cook 3-4 minutes, or until bubbles form over the surface of the pancake, then flip and cook an additional 2-3 minutes.
Serve warm with sliced bananas, butter, and syrup.