Put peanut butter into a mixing bowl and stir in 1/2 cup Cool Whip. Once that is blended, stir in another 1/2 cup and blend it in. Add a final 1/2 cup of Cool Whip and blend.

Set out mini cupcake papers on a shallow pan.

Using a cookie scoop or pastry bag, scoop or pipe mousse into cupcake papers. Set pan in freezer for several hours. Transfer mini mousses to a ziplock bag and keep frozen until right before serving.