Line 2 baking sheets with parchment paper. Set aside.
In the bowl of a stand mixer fitted with the paddle attachment, cream the powdered sugar, peanut butter, butter, vanilla, and salt together until creamy and incorporated, about 2-3 minutes.
4 cups powdered sugar, 1½ cups creamy peanut butter, ½ cup salted butter, 1½ teaspoons pure vanilla extract, 1 teaspoon kosher salt
Shape the dough into 1-inch balls and refrigerate until firm, about 1 hour.
When the dough is completely chilled, microwave the chocolate chips and shortening (or oil), stirring every 15 seconds, on HIGH until most of the chips are melted. Remove from the microwave and stir until smooth and all chips are melted.
12 ounces semisweet chocolate chips, 1 tablespoon vegetable shortening
Insert a toothpick in the top-middle of a peanut butter ball and dip ⅔ of it in the melted chocolate. Let the excess chocolate drip into the bowl, and place the buckeye on the prepared baking sheet. Repeat with all peanut butter balls. (Note: If the chocolate begins to thicken, microwave for a few seconds until desired consistency.)
Refrigerate the Buckeyes in a covered container until firm before serving.