Beat together your peanut butter and butter till smooth.
Add in your powdered sugar, milk and vanilla and stir till a smooth frosting is formed. (Add a little more powdered sugar, or a little milk if needed for the consistency)
Spread frosting on top of 1 cookie generously, and then top with a second cookie.
Repeat with additional cookies and frosting.
Microwave chocolate chips and coconut oil in a small microwave safe bowl for 1 minute. Allow to rest for 30 seconds, then stir till smooth.
Dip cookies half way into melted chocolate and place on waxed paper.
Allow to set till chocolate is hardened.