Chill your tools: Place a mixing bowl and beaters in the fridge for 10 minutes if you’re making fresh whipped cream. Cold tools whip faster and create better volume.
Make the pudding: In a large bowl, whisk instant vanilla pudding mix with cold milk according to package directions. Stir in 1 teaspoon vanilla extract if using.
Let it thicken for 5 minutes.
Whip the cream (if not using whipped topping): Beat heavy cream with 1–2 tablespoons powdered sugar until medium peaks form. Don’t overwhip. Set aside.
Lighten the pudding: Fold half of the whipped cream (or an equal amount of whipped topping) into the pudding to make it extra creamy.
Reserve the rest for topping.
Prep the bananas: Peel and slice bananas into 1/4-inch rounds. If desired, lightly brush with lemon juice to slow browning. Blot any excess to avoid a sour taste.
Layer the cups: Add a few vanilla wafers to the bottom of each cup, breaking them if needed to fit.
Spoon a layer of pudding over the wafers, then add a layer of banana slices.
Repeat: Continue layering wafers, pudding, and bananas until cups are nearly full. End with pudding for a smooth top.
Top and garnish: Add a dollop of the remaining whipped cream or whipped topping. Crumble a few wafers or place one whole wafer on top.
Add a fresh banana slice right before serving, if desired.
Chill: Refrigerate at least 30–60 minutes to let the flavors meld and wafers soften slightly. For softer wafers, chill 2–4 hours.
Serve: Keep chilled until ready to eat. Enjoy straight from the cup with a spoon.