01 -
Line an 8x8-inch baking pan with parchment paper, leaving an overhang to lift the fudge out. Lightly spray the parchment paper with nonstick cooking spray.
02 -
In a heavy-bottomed saucepan, combine sugar, butter, heavy cream, and corn syrup. Cook over medium heat, stirring constantly, until it reaches a rolling boil.
03 -
Continue stirring the boiling mixture for 4-5 minutes or until a candy thermometer registers 235-240°F (soft-ball stage).
04 -
Remove the saucepan from heat. Stir in the chopped white baking chocolate until fully melted and smooth.
05 -
Mix in the marshmallow cream and vanilla extract until well combined.
06 -
Pour ¾ of the fudge mixture into the prepared baking dish.
07 -
Add unsweetened cocoa powder to the remaining fudge mixture and whisk until fully incorporated.
08 -
Carefully spoon the cocoa-flavored mixture over the white layer. Use a toothpick or skewer to create a marbled effect.
09 -
Let the fudge cool at room temperature for 1 hour. Then, cover with aluminum foil and refrigerate for 1 hour, or until set. Alternatively, allow it to set on the counter if the kitchen is cool.
10 -
Lift the fudge out of the pan using the parchment overhang. Slice into 25 or 36 squares using a sharp kitchen knife.
11 -
Combine chocolate chips and vegetable oil in a microwave-safe bowl. Microwave on high for 30 seconds, stir, and repeat in 15-second intervals until melted.
12 -
Dip the tops of the fudge squares into the melted chocolate. Allow the chocolate to set completely before serving.