Prepare your 9×9 pan with parchment and nonstick spray.
Mix banana flavoring and yellow gel in a small bowl; set aside.
Heat butter, cream, and sugar until simmering, stirring constantly for 6–7 minutes.
Add white baking chips, cover, and rest 3–4 minutes, then stir smooth.
Fold in marshmallow fluff.
Add banana mixture and stir until evenly colored.
Spread in pan, garnish with wafers, and chill 4 hours before slicing.
