Line a baking sheet with parchment paper and set aside.
In a medium saucepan, combine the peanut butter, butter, and brown sugar over medium heat.
Heat until melted and starting to simmer, stirring constantly.
Remove from the heat.
Add the powdered sugar a 1⁄4 cup at a time, stirring until completely combined with the peanut butter mixture after each addition.
Set aside and let cool for 5 min (if it cools completely it will harden and you’ll need to start over.)
Using a medium cookie scoop or a heaping tablespoon, scoop out peanut butter mixture and shape into eggs or press into mini cupcake liners.
For the eggs:
Roll the scoop into a ball, and then roll it into a short cylinder.
Place it on the baking sheet, and then use your fingers to shape the ends into an egg-like oval.
For regular cups:
Press ½ tablespoon worth of filling into the mini cupcake liner and place on a baking sheet.
Refrigerate to allow the peanut butter treats to set, about 30 minutes
Once set, melt the chocolate chips and oil together in the microwave on 50% power in 30-second increments, stirring after each, until completely melted.
One at a time, dip a peanut butter egg into the chocolate and, using a fork, flip it over so it is completely covered.
Remove it from the bowl, letting any excess chocolate drip off.
Return it to the baking sheet, and repeat with all of the treats.
Sprinkle with decorations, if desired.
Return the chocolate-covered peanut butter treats to the refrigerator to allow the chocolate to set, about 30 minutes..