Step 1

Line a small 4x6-inch or 5x5-inch dish with foil leaving an overhang on the sides to lift the fudge out of the pan easily.Pro Tip: You can use a sheet of wax paper instead of foil but I prefer using foil because it conforms to the shape of the dish better than wax paper. The foil allows the fudge to be lifted out of the pan in one piece. It is also easier to cut the fudge outside the pan which allows for more evenly cut pieces.

Step 2

Melt butter in a 2-quart saucepan over medium-low heat.

Step 3

Stir in the peanut butter and continue stirring until smooth.

Step 4

Remove the pan from the heat and stir in the vanilla extract.

Step 5

Add the sifted powdered sugar and stir until smooth.Pro Tip: To sift powdered sugar, place the sugar in a fine-mesh strainer or sifter placed over a bowl. Hold the strainer in one hand and gently tap its side with the palm or a finger from the opposite hand. Sifting powdered sugar is an important step because there are often hard, round nuggets in powdered sugar and if not sifted, the nuggets will cause the fudge to be gritty or you'll end up with pockets of sugar in your fudge.

Step 6

Pour the fudge into the baking dish and smooth the top with the back of a spoon or rubber spatula.

Step 7

Cover tightly and refrigerate for at least 4 hours or until firm.

Step 8

Remove the fudge from the refrigerator and cut into pieces.

Step 9

Store this fudge in an airtight container. The fudge keeps well for up to a week at room temperature or for 2 weeks if refrigerated.To freeze, wrap the fudge in plastic wrap and transfer it to a freezer storage bag. Freeze for up to 1 month and thaw in the refrigerator.