Step 1

Beat 1 cup cold heavy cream, 2 tablespoons powdered sugar, and 1 teaspoon vanilla extract with the whisk attachment in a stand mixer on medium speed until soft peaks form, 3 to 4 minutes. Add 1/2 cup marshmallow crème and beat on medium speed until stiff peaks form, 1 to 2 minutes.

Step 2

Fold 2 diced ripe bananas and 16 crushed vanilla wafer cookies into the cream with a flexible spatula until just combined.

Step 3

Divide between 4 serving cups. Garnish with sliced bananas and more crushed vanilla wafer cookies if desired. Serve immediately.