Preheat the oven to 350°F. Line a 12-cup muffin tin with cupcake liners.

In a medium bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.

In a large bowl, cream the softened butter and granulated sugar together until light and fluffy, about 3-4 minutes.

Add the eggs one at a time, mixing well after each addition. Stir in the vanilla extract and mashed bananas.

Gradually add the dry ingredients to the wet mixture, alternating with the buttermilk. Start and end with the dry ingredients. Mix until just combined.

Divide the batter evenly among the cupcake liners, filling each about two-thirds full. Bake for 18-20 minutes, or until a toothpick inserted into the center comes out clean.

Let the cupcakes cool in the pan for 5 minutes, then transfer them to a wire rack to cool completely.

While the cupcakes cool, prepare the pudding filling. In a medium bowl, whisk together the instant pudding mix, cold milk, and vanilla extract until smooth. Refrigerate for about 5 minutes to thicken.

Once the cupcakes are cool, use a small knife or cupcake corer to remove a small portion from the center of each cupcake. Fill the holes with the prepared pudding.

For the topping, beat the heavy whipping cream, powdered sugar, and vanilla extract in a mixing bowl until stiff peaks form.

Frost the filled cupcakes with the whipped cream and garnish with crushed vanilla wafers and sliced bananas.