In a mixing bowl, combine the heavy cream and instant vanilla pudding mix. Whip them together on medium speed for 1-2 minutes until thick and fluffy. Transfer to fridge to chill for 30-45 minutes.

Preheat your oven to 350°F (175°C). Prepare cupcake tins with liners.

In a large bowl, whisk together cake flour, granulated sugar, baking soda, baking powder, and fine salt.

Add melted butter, pure extracts, and eggs to the dry mixture. Mix gently, then fold in sour cream and buttermilk until combined.

Fill liners with batter 2/3 full. Bake for 18-20 minutes or until a toothpick comes out clean. Let cool in the tin for 10 minutes.

Beat room-temperature butter on high speed for about 10 minutes until pale and fluffy. Gradually add extracts and salt, then mix in powdered sugar and heavy cream until smooth.

Once cupcakes are cool, use a small knife to remove a portion from each center and fill with chilled pudding filling.

Pipe the banana buttercream frosting around the edges of each cupcake, leaving the pudding filling visible. Top with crushed Nilla wafers and a whole Nilla wafer.