Place a metal mixing bowl (glass is okay too) and beaters in the freezer for 20 minutes.
Melt the 1/2 cup of chocolate chips with a little bit of vegetable oil and microwave on 50% power for 1-2 minutes until melted. Set aside.
Heat 1 tablespoon of creamy peanut butter in a microwave safe bowl, until melty. Drizzle the melted peanut butter on the inside of the jars you’re going to put the mousse in. Set the jars aside.
In a small container, sprinkle the gelatin over the cold water. Allow the mixture to bloom for 1 minute, then heat in the microwave for 10-15 seconds to melt the mixture. Set aside.
Remove the bowl and beaters from the freezer. Add the heavy cream and International Delight Reese’s creamer, beat on high until soft peaks form.
Add in the melted gelatin mixture and melted chocolate, beat on high until airy and thick. Transfer the mousse to a piping bag and pipe into the jars. Refrigerate for 1 hour, or overnight. You can definitely refrigerate it overnight (I do!) but be sure to cover your bowls/jars with plastic wrap otherwise the top of the mousse can dry out.
Make chocolate peanut butter bark as a decorative topping. Melt 1/2 cup of chocolate candy melts (or chocolate candiquik/almond bark) - once melted pour on a small baking sheet lined with parchment paper. Drizzle melted peanut butter and swirl. Add pieces of a reese’s cup and peanut butter chips. Place in the fridge to set.
Before serving, break the bark into pieces and top each jar of mousse with a few pieces.