Brown the butter by melting in a medium saucepan over medium heat until golden amber and nutty aroma develops, about 5-7 minutes. Let cool slightly.

In a large bowl, mash the ripe bananas until smooth. Combine with brown sugar and granulated sugar until thick.

Incorporate cooled brown butter into the banana mixture, stirring until smooth.

Add Greek yogurt, eggs, and vanilla, whisk until creamy and well-blended.

In another bowl, whisk together flour, baking soda, baking powder, salt, and cinnamon. Gradually mix dry ingredients into wet until just combined.

Preheat oven to 350°F (175°C). Fill cupcake liners ⅔ full with batter and bake for 18-20 minutes until a toothpick comes out clean.

Prepare pudding filling by whisking instant pudding mix with milk until smooth and refrigerate to set.

For buttercream, beat softened butter until fluffy, gradually add powdered sugar and heavy cream until light and pipeable.

Cool cupcakes completely, fill with pudding using a cupcake corer.

Frost with buttercream and sprinkle crushed Nilla wafers and optional sliced bananas on top.