Line cookie sheet with non-stick foil or wax paper sprayed with baking spray.
Mix butter and peanut butter together in a bowl.
Add 2 1/2 cups powdered sugar and mix until the sugar has disappeared.
The mixture should be the consistency of a peanut butter cup center and doesn't stick to your hands when rolling. Add more powdered sugar a tablespoon at a time until that consistency is reached.
Roll peanut butter mixture into equal-sized balls.
Set balls on the prepared cookie sheet.
Place cookie sheet in the refrigerator and leave until balls are firm, at least 60 minutes.
Melt chocolate in a double boiler set to simmer. A microwave can be used by microwaving chocolate and shortening in 30-second intervals, stirring in between each interval. This method may require reheating during the coating step.
Place a sheet of wax paper, parchment paper, or aluminum foil on another cookie sheet and place it on workspace near the chocolate.
Remove the balls from the refrigerator.
Remove balls, one at a time using a toothpick or candy dipping tool.
Dip 2/3 of the ball into the chocolate, leaving the top 1/3 uncoated.
Let excess chocolate drip back into melted chocolate.
Set coated balls on lined cookie sheet.
Place the coated balls back into the refrigerator until the chocolate has set.
Store in an airtight container at room temperature for up to 1 week, the refrigerator for up to 3 weeks, or the freezer for up to 3 months.
Notes
Add 1/4 teaspoon salt if unsalted butter is used.
12 ounces of chocolate chips combined with 1 tablespoon of coconut oil, or 1 ounce of food grade paraffin wax can be substituted for melting wafer.
Use butter than has been completely softened so you don’t get butter pieces in the mixture.
Add additional peanut butter, 1 tablespoon at a time to dough that is too crumbly to roll into balls.
Use a cookie scoop for uniform sized balls.
For the best results, only use peanut butter balls that are well chilled.
If the dough becomes to soft to work with, lace it back into the refrigerator until well chilled.
Frozen dough balls will sweat when coming to room temperature. Chocolate won’t stick and may seize from the water.
Silicone mold can be used to form the dough into shapes and covered completely in chocolate for homemade holiday shaped peanut butter cups.