Carefully separate the cookie halves, leaving cream on 1 half of each cookie. Keep the cream sides and put the chocolate wafer sides into a ziploc bag. You can keep those in the freezer for making a future chocolate cookie pie crust.
Take an Oreo half (cream side up) and top it with a peanut butter cup. Then set another Oreo half (cream side down) on top of the peanut butter cup and gently press down.
Place on a baking sheet lined with parchment paper or a silicone baking mat and repeat with the remaining cookies and Reese’s cups.
In a microwave safe bowl, combine chocolate chips and 2 tbsp vegetable oil. Microwave in 30 second intervals, stirring in-between, until melted and smooth.
Coat the peanut butter cup Oreos in the melted chocolate with a fork, tapping the fork against the side of the bowl to allow the excess chocolate to drip off, then return to the prepared baking sheet.
Once all the Oreos are dipped, combine peanut butter chips and 1 tbsp vegetable oil in another microwave safe bowl and microwave in 30 second intervals, stirring in-between, until melted and smooth.
Drizzle the melted peanut butter chips over each chocolate coated Oreo, then transfer to the fridge to set the chocolate. Once set, carefully break off the excess candy-coating pieces around each cookie before enjoying!