Step 1

Line an 8×8 baking pan with parchment paper and set aside.

Step 2

Place the semi-sweet chocolate chips in a heat-safe medium bowl and add 1 tablespoon of butter and ¾ cup of the sweetened condensed milk (half a can). Microwave in 30-second increments, stirring in between each interval, until the chocolate is fully melted. Once the chocolate is melted, stir in 1 teaspoon of vanilla extract.

Step 3

Spread the mixture into the prepared baking pan. Allow that mixture to chill in the refrigerator for 15-20 minutes, or until the chocolate has set up.

Step 4

Once the semi-sweet chocolate layer of fudge has been set up, prepare the white chocolate layer. Place the white chocolate chips in a heat-safe medium bowl and add 1 tablespoon of butter and ¾ cup of the sweetened condensed milk (the remaining amount in the can). Microwave in 30-second increments, stirring in between each interval, until the chocolate is fully melted. Once the chocolate is melted, stir in 1 teaspoon of vanilla extract.

Step 5

Pour the white chocolate layer over the chocolate layer of fudge, using an offset spatula to spread if needed. Immediately sprinkle the nonpareils over the white chocolate layer.

Step 6

Cover the pan with a lid or plastic wrap and refrigerate until the fudge is set, 2-3 hours. I find overnight is best, in terms of flavor and firmness of the fudge.

Step 7

Once set, remove the fudge, using the parchment paper from the pan cut it into 1-inch pieces.