White Chocolate Snowballs

Line 1 large baking sheet with aluminum foil and another with waxed paper; set both aside. Using an electric mixer (or a wooden spoon), beat together the peanut butter and butter in a large bowl until blended and smooth. Add the sugar, 1/2 cup at a time; blend until smooth. Press the mixture into 1-inch balls. (The dough will be dry, so it may be easier to form with damp hands.) Place the balls on the foil-lined sheet. Let stand until firm, about 30 minutes. Melt the white chocolate chips and shortening in a heatproof bowl set atop a pot of simmering water over medium-high heat. Stir continuously until smooth. Remove the pan from the heat. Using a toothpick for a handle, pierce each ball, then dip it into the melted chocolate. Spoon chocolate over the balls to coat them, if needed. Set them on the waxed-paper-lined sheet and top each with a peanut half. Refrigerate until set, about 30 minutes. Store in an airtight container in the refrigerator.