01 - Line an 8x8-inch baking pan with parchment paper, leaving an overhang on opposite sides for easy removal.
02 - Combine chocolate cookie crumbs and melted butter in a medium bowl. Mix until evenly moistened. Press firmly into the bottom of the prepared pan to create an even crust layer.
03 - Place white chocolate chips in a heatproof bowl set over a pan of simmering water, creating a double boiler. Stir constantly until completely smooth and melted. Remove from heat.
04 - Beat softened cream cheese in a large bowl until completely smooth and creamy, with no lumps remaining.
05 - Add melted white chocolate, sweetened condensed milk, Irish cream liqueur, peppermint extract, and salt to the cream cheese. Beat until thoroughly combined and silky smooth. Stir in green food coloring drop by drop until desired color is achieved.
06 - Pour cheesecake fudge mixture over the prepared crust. Smooth top with a spatula. Refrigerate for at least 3 hours until completely set and firm.
07 - Once set, drizzle with melted dark chocolate and sprinkle with green decorations if desired. Lift from pan using parchment overhang. Cut into 16 squares using a sharp knife, wiping blade clean between cuts.