01 - Line an 8-inch square baking pan with parchment paper, leaving an overhang on opposite sides for easy removal later.
02 - In a medium saucepan over low heat, combine white chocolate chips, sweetened condensed milk, and cubed butter. Stir constantly until completely melted and smooth, ensuring the mixture doesn't scorch.
03 - Remove from heat. Stir in heavy cream, Irish cream coffee creamer, vanilla extract, espresso powder (if using), powdered sugar, and salt. Mix until fully incorporated and mixture is silky and uniform.
04 - Pour the fudge mixture into the prepared pan. Use a spatula to spread evenly and smooth the top surface. Tap the pan gently on the counter to release any air bubbles.
05 - Refrigerate for at least 2 hours or until completely firm and set throughout.
06 - Lift the fudge from the pan using the parchment overhang. Cut into 36 equal squares using a sharp knife. Store in an airtight container in the refrigerator.