01 - Line an 8-inch square baking pan with parchment paper, allowing an overhang on opposite sides for easy removal of the fudge later.
02 - Combine white chocolate chips, sweetened condensed milk, and butter in a medium saucepan over low heat. Stir continuously until completely melted and smooth, ensuring the chocolate doesn't scorch.
03 - Remove saucepan from heat. Whisk 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 surface. Tap the pan gently on the counter to release any air bubbles.
05 - Refrigerate for at least 2 hours until completely firm and set throughout.
06 - Lift the fudge from the pan using the parchment paper overhang. Cut into 36 equal squares using a sharp knife. Store in an airtight container in the refrigerator.