Preheat the oven to 350°F (175°C). Lightly grease a 9×13-inch baking dish.
In a large bowl, mash the bananas. Add granulated sugar, brown sugar, oil, milk, vinegar, and vanilla extract. Mix until smooth.
In a separate bowl, whisk together flour, baking powder, baking soda, salt, and cinnamon.
Gradually stir the dry ingredients into the wet ingredients until just combined. Don’t overmix.
Pour the batter into the prepared dish. Bake for 35-38 minutes, or until a toothpick inserted in the center comes out clean.
Let the cake cool completely before topping.
While the cake cools, whisk the banana pudding mix with 2 cups of cold milk for about 2 minutes until it thickens. Chill in the fridge for 5-10 minutes.
Spread the chilled pudding evenly over the cooled cake.
Top with whipped cream, then crush a few vanilla wafers and sprinkle on top. You can add whole wafers too for decoration.
Slice and serve chilled or at room temp. Store leftovers covered in the fridge.