01 -
Line an 20 cm x 20 cm baking pan with crisscrossed parchment paper, leaving a 5 cm overhang on all sides. Lightly grease with cooking spray.
02 -
In a medium heatproof bowl, microwave semisweet chocolate chips, sweetened condensed milk, and chopped bittersweet chocolate in 30-second intervals, stirring between each, until smooth and melted, about 90 seconds total. Transfer mixture to a medium pot.
03 -
In a small bowl, mix marshmallow fluff, espresso powder, unsalted butter, and Kahlúa. Scrape this mixture into the pot and cook over medium heat, stirring, until heated through, about 1 minute. Pour the mixture into the prepared pan and smooth the surface. Wipe out the pot.
04 -
In a medium heatproof bowl, microwave white chocolate chips and sweetened condensed milk in 30-second intervals, stirring between each, until melted and smooth, about 90 seconds total. Transfer to the reserved pot.
05 -
In a small bowl, mix marshmallow fluff, unsalted butter, Baileys Irish Cream, and Kahlúa. Scrape the mixture into the pot and cook over medium heat, stirring, until heated through, about 1 minute. Pour this mixture evenly over the bottom layer and smooth the top.
06 -
Refrigerate the layered dessert until firm, at least 2 hours and up to 5 days.
07 -
Use parchment overhangs to lift set fudge from the pan and transfer to a cutting board. Dust with espresso powder and cut into squares. Top each piece with espresso beans if desired.