Preheat your oven to 275°F (135°C) and grease a 9-inch springform pan thoroughly.

In a small bowl, mash your very ripe bananas and mix in the white vinegar. Set aside.

In a larger mixing bowl, cream together melted unsalted butter and sugar with a hand mixer until pale and fluffy, about 2-3 minutes.

Incorporate the egg and vanilla extract into the mixture, blending until fully combined.

Gradually mix in half of the flour along with baking soda and salt, then add half of the milk, stirring gently.

Repeat with remaining flour, baking soda, and milk, then fold in the banana mixture.

Pour the batter into the prepared springform pan and bake for about 1 hour or until a toothpick comes out clean.

Cool the cake in the pan for 10-15 minutes before releasing the sides.

To make the whipped cream, whip the heavy cream until soft peaks form, then add powdered sugar and peanut butter, and continue whipping.

Slice the cooled cake and generously top each slice with peanut butter whipped cream.