01 -
Line an 8 x 8 inch baking dish with parchment paper, leaving an overhang for easy removal.
02 -
Lightly spray parchment with nonstick cooking spray.
03 -
Place semi-sweet chocolate chips, milk chocolate chips, sweetened condensed milk, hot chocolate mix, and butter into a microwave-safe bowl.
04 -
Microwave on high for 1 minute, stir, then continue microwaving in 45-second increments, stirring after each, until melted and smooth (approximately 2 1/2 to 3 minutes total).
05 -
Stir in vanilla extract until fully blended.
06 -
Gently fold 2 cups of miniature marshmallows into the chocolate mixture, reserving the remaining 2 cups for topping.
07 -
Microwave the mixture for an additional 20 to 30 seconds, stirring 2 to 3 times for even distribution.
08 -
Pour the fudge mixture into the prepared dish and spread evenly using a spatula.
09 -
Scatter remaining 2 cups miniature marshmallows over the surface, pressing gently to secure.
10 -
Cover with plastic wrap and refrigerate for at least 2 hours or until the fudge is firm.
11 -
Lift fudge from the pan using parchment overhang and transfer to a cutting surface.
12 -
Melt 1/2 cup semi-sweet chocolate chips with 2 teaspoons vegetable oil in a microwave-safe bowl for 30 seconds, stirring until smooth.
13 -
Drizzle melted chocolate over marshmallow topping and allow it to set before cutting into 25 squares.
14 -
Store fudge squares refrigerated until ready to serve.