Step 1: Line an 8-inch-square baking pan with wax paper or foil, and coat with non-stick spray.

Step 2: In a microwave-safe bowl, combine the dark chocolate chips, heavy cream and half of the sweetened condensed milk. Microwave the dark chocolate mixture in 20-second intervals, stirring in between each interval, until the chocolate is melted.

Step 3: Add the vanilla extract to the dark chocolate mixture and stir well until smooth.

Step 4: Transfer the dark chocolate mixture into the prepared pan and spread into an even layer.

Step 5: In a separate bowl, combine the white chocolate chips with the remaining half of the sweetened condensed milk. Microwave the white chocolate mixture in 20-second intervals, stirring in between each interval, until the chocolate is melted.

Step 6: Evenly spread the white chocolate mixture on top of dark chocolate layer.

Step 7: Top the chocolate layers with the Mallow Bits or miniature marshmallows, and gently press them down.

Step 8: Refrigerate for 4 hours, or until set.

Step 9: Remove the fudge and wax paper from the pan. Carefully peel all of the wax paper from the fudge.

Step 10: Cut the fudge into bite-sized pieces and serve.