01 - Combine peanut butter and cream cheese in a large mixing bowl. Beat with an electric mixer until completely smooth and creamy, approximately 2 minutes.
02 - Add powdered sugar to the bowl and mix until fully incorporated and no lumps remain, about 1 minute.
03 - Gently fold in the thawed Cool Whip using a spatula with light, sweeping motions. Mix only until combined and airy—avoid overmixing to maintain the light texture.
04 - Distribute the mousse evenly into 6 serving glasses or bowls. Refrigerate for at least 1 hour before serving to allow the flavors to meld and the texture to set.
05 - Just before serving, top with chopped roasted peanuts and chocolate shavings or mini chocolate chips if desired.