Pour the instant pudding mix into a large mixing bowl. Add the heavy whipping cream in place of milk, following the liquid measurements on the pudding box but substituting cream completely.

Using a hand mixer, blend on low speed until the mixture begins to combine, then switch to medium-high and beat until thick, smooth, and slightly fluffy.

Place the bowl in the refrigerator for a few minutes to allow the mousse to thicken and set. After chilling, whip the mousse again briefly with the hand mixer to achieve an ultra-thick, creamy consistency.

Spoon the mousse into small bowls, ramekins, or dessert glasses. Serve immediately if you like a soft, airy texture, or chill for 20–30 minutes for a firmer consistency.