1-First Step: Prep and mise en place Line an 8×8 baking pan with parchment paper and spray the paper lightly with nonstick cooking spray so the fudge lifts out easily. Measure and divide the sweetened condensed milk into two equal portions of 7 oz each. Place one 7 oz portion with the semi-sweet chocolate chips in a microwave-safe bowl, and the other 7 oz portion with the white chocolate chips in a separate microwave-safe bowl. Keep the 2 tsp vanilla extract handy, split into two 1 tsp portions.

2-Second Step: Melt the semi-sweet layer Microwave the semi-sweet chocolate and 7 oz sweetened condensed milk in 30-second intervals. After each 30-second burst, stir vigorously to distribute heat. Continue until the mixture is smooth and glossy this usually takes 60 to 90 seconds total, depending on your microwave. Stir in 1 tsp vanilla extract. Be careful not to overheat; overheating can cause the chocolate to seize or become grainy.

3-Third Step: Spread the base layer Pour or spread the melted semi-sweet chocolate mixture evenly into the prepared 8×8 pan. Use an offset spatula or the back of a spoon to smooth the surface so the top layer sits flush. For best results, work while the mixture is still warm but not hot this helps the white chocolate layer adhere later.

4-Fourth Step: Melt the white chocolate layer In the separate bowl, melt the white chocolate chips with the other 7 oz of sweetened condensed milk using the same microwave method: 30-second bursts with stirring in between. White chocolate overheats easily, so keep the intervals short and stir often until silky. Stir in the remaining 1 tsp vanilla extract. Once smooth, fold in 2 tbsp Christmas sprinkles so colors and crunch are incorporated in the white layer.

5-Fifth Step: Layer and top Spread the white chocolate fudge gently on top of the semi-sweet layer. Work quickly but gently spreading while the bottom layer is still slightly warm helps the layers bond and reduces separation. Add extra Christmas sprinkles on top for a festive look. If you prefer, sprinkle a few crushed candy canes or crushed cookies for a textured finish.

6-Final Step: Chill, slice, and serve Chill the pan in the refrigerator for at least one hour, or until fully set. For best results, chill 2-4 hours for firm slices. Once set, lift the parchment to remove the fudge slab and slice into 1-inch squares. A warm, clean knife gives the best cuts. Store in an airtight container in the refrigerator for up to 3 weeks, or freeze for up to 3 months.