01 - Line an 8x8-inch baking pan with parchment paper, allowing excess paper to hang over two opposite sides for easy removal later.
02 - Combine chocolate cookie crumbs with melted butter in a medium bowl until evenly moistened. Press firmly into the bottom of the prepared pan using the back of a spoon or measuring cup to form an even, compact layer.
03 - Set up a double boiler by placing a heatproof bowl over a pot of simmering water, ensuring the bowl doesn't touch the water. Add white chocolate chips and stir constantly until completely melted and smooth. Remove from heat.
04 - In a large mixing bowl, beat the softened cream cheese with an electric mixer until completely smooth and creamy, approximately 2 minutes.
05 - Pour the melted white chocolate into the cream cheese along with sweetened condensed milk, Irish cream liqueur, peppermint extract, and salt. Beat on medium speed until thoroughly combined and silky smooth, about 2 minutes. Add green food coloring drop by drop if desired, mixing until uniform color is achieved.
06 - Pour the cheesecake fudge mixture over the prepared crust. Use an offset spatula to spread evenly and create a smooth surface.
07 - Refrigerate for at least 3 hours or overnight until completely firm and set throughout.
08 - Once fully set, drizzle melted dark chocolate over the surface in a decorative pattern. Immediately sprinkle with green sprinkles or edible glitter while chocolate is still wet.
09 - Using the parchment paper overhang, lift the entire slab out of the pan. Cut into 16 equal squares with a sharp knife, wiping the blade clean between each cut for clean edges.