In a large mixing bowl, beat 1 1/2 cups smooth peanut butter, 1/2 cup salted butter, softened, 1 teaspoon vanilla extract, and 1/4 teaspoon table salt with a stand mixer until smooth and fluffy.
Add 3 cups powdered sugar, one-half cup at a time, beating on low speed until fully combined. The mixture should be firm enough to roll.
Scoop about one tablespoon of the mixture with a cookie scoop and roll it into a ball between the palms of the hands. Set each ball on a parchment-lined baking sheet. Repeat until all the mixture is used.
Freeze the balls for 15 to 20 minutes, until firm.
Place 1 cup dark chocolate melting wafers in a small microwave-safe bowl. Microwave at 50 percent power for one minute, stir, then continue in 30-second increments at 50 percent power, stirring between each, until fully smooth.
Insert a skewer into the top of a chilled ball and dip it into the chocolate, leaving a circle of peanut butter showing at the top. Set it back on the parchment to let the chocolate set.
Smooth over the hole left by the skewer with a finger. Repeat with the remaining balls.
Notes
Keep refrigerated until ready to serve.
Store in an airtight container in the refrigerator for up to two weeks, or freeze for up to three months.