• Step 1: In a large mixing bowl, combine the peanut butter and softened butter. Use a hand mixer or stand mixer to cream the ingredients together until smooth and well-blended.
• Step 2: Gradually add the powdered sugar to the peanut butter mixture, mixing on low speed until the sugar is fully incorporated and the filling is smooth and creamy. Stir in the vanilla extract.
• Step 3: Press the peanut butter filling into an 8×8-inch baking pan, using your hands or the back of a spoon to create an even layer.
• Step 4: In a microwave-safe bowl, melt the chocolate chips in 30-second intervals, stirring between each, until smooth and completely melted.
• Step 5: Pour the melted chocolate over the peanut butter layer and use a spatula to spread it into an even, smooth layer, covering the entire surface.
• Step 6: Refrigerate the pan for at least 2 hours, or until the chocolate is completely set.
• Step 7: Once set, remove the pan from the refrigerator and use a sharp knife to cut the peanut butter squares into 16 equal pieces.