01 - Combine the peanut butter and softened cream cheese in a large mixing bowl. Beat with an electric mixer until the mixture is completely smooth and creamy, with no lumps remaining.
02 - Pour in the powdered sugar and mix on medium speed until fully incorporated and the mixture appears glossy and uniform.
03 - Gently fold the thawed Cool Whip into the peanut butter mixture using a spatula. Mix just until combined and airy, taking care not to overmix or deflate the light texture.
04 - Distribute the mousse evenly among 6 serving glasses, bowls, or ramekins, smoothing the tops with the back of a spoon.
05 - Refrigerate for at least 1 hour to allow the mousse to set and develop optimal texture before serving.
06 - Sprinkle with chopped roasted peanuts and chocolate shavings or mini chocolate chips just before serving, if desired.