In a stand mixer, combine heavy cream and instant vanilla pudding mix. Whip on medium speed until well blended and creamy, about 3-5 minutes. Transfer the mixture into a bowl, cover it with plastic wrap, and chill in the refrigerator for 30 to 45 minutes.

Preheat your oven to 350℉ (175℃) and line your cupcake tins with liners.

Whisk together the cake flour, granulated sugar, baking soda, baking powder, and fine salt until thoroughly combined.

Gradually blend the melted unsalted butter, pure vanilla extract, banana extract, eggs, sour cream, and buttermilk into the dry ingredients.

Fill the cupcake liners about two-thirds full with the batter and bake for 18-20 minutes or until a toothpick inserted comes out clean.

In a separate bowl, beat room temperature unsalted butter until pale and fluffy. Gradually mix in the banana extract, powdered sugar, and heavy cream until smooth.

Once the cupcakes are cooled, remove the center of each cupcake and fill with chilled pudding filling.

Pipe the banana buttercream frosting around the edges of each cupcake and top with additional pudding and crushed Nilla wafers.