Begin by melting your salted butter in a saucepan over medium heat. Stir continuously for about 5-7 minutes until the butter turns a golden amber color and emits a rich, nutty aroma. Be sure to watch closely to prevent burning! Once browned, remove it from the heat and let it cool while you prepare the other ingredients.

In a large mixing bowl, mash 2-3 ripe bananas until smooth, ensuring there are no lumps. Add both brown and granulated sugars to the mashed bananas, mixing well. Incorporate your cooled brown butter into the banana-sugar mixture, stirring until everything is combined and creamy.

Next, whisk in ½ cup of Greek yogurt (or sour cream), 2 large room temperature eggs, and 1 teaspoon of vanilla bean paste until you achieve a smooth, homogenous batter.

In a separate bowl, combine 1 ½ cups of all-purpose flour, 1 teaspoon of baking soda, 1 teaspoon of baking powder, ½ teaspoon of salt, and optional ½ teaspoon of ground cinnamon. Use a whisk to blend these dry ingredients uniformly, ensuring no clumps remain.

Gradually incorporate the dry ingredients into your wet banana batter, stirring gently. Be careful not to overmix; you should combine just until you no longer see dry flour.

Preheat your oven to 350°F (175°C). Line a standard muffin tin with cupcake liners, then evenly fill each liner with your batter, around ¾ full. Bake in the preheated oven for 18-20 minutes.

While the cupcakes cool, prepare the creamy filling by whisking together 1 package of instant pudding mix with 2 cups of milk in a mixing bowl. Stir until the mixture thickens, about 2 minutes.

To create the rich buttercream frosting, beat together ½ cup of softened butter and 2 cups of powdered sugar in a mixing bowl until creamy. Gradually add in 2 tablespoons of heavy cream while beating until the frosting is fluffy and light.

Once the cupcakes are completely cool, create a hollow center in each cupcake. Carefully fill each cavity with the prepared pudding filling.

Top each filled cupcake with a generous swirl of your fluffy buttercream using a piping bag. Sprinkle crushed Nilla wafers on top and finish with a few slices of banana for garnish.