Line a 9x9 inch baking pan with parchment paper and lightly grease it.

In a large pot, melt butter over medium-low heat. Add marshmallows and stir until completely melted and smooth. Remove from heat.

Stir in the vanilla extract. Gently fold in the crispy rice cereal and crushed vanilla wafers until fully coated.

Transfer the mixture to the prepared pan. Gently press it into an even layer without packing it down too tightly. Let cool.

In a bowl, whisk together the dry pudding mix and powdered sugar. Add heavy cream 1 tablespoon at a time, whisking until you reach a thick, pourable glaze consistency.

Pour the glaze over the cooled cereal treats, spreading evenly so it drips into the crevices.

Toss sliced bananas lightly in lemon juice and arrange on top of the wet glaze. Let set for 30 minutes before cutting into thick squares.