01 - Line an 8-inch square baking pan with parchment paper, leaving an overhang for easy removal.
02 - Combine white chocolate chips, sweetened condensed milk, and butter in a medium saucepan over low heat. Stir constantly until melted and smooth.
03 - Remove from heat. Add heavy cream, Irish cream-flavored coffee creamer, vanilla extract, instant espresso powder if using, powdered sugar, and salt. Stir until fully combined and silky.
04 - Pour mixture into prepared pan and smooth top with spatula. Refrigerate for at least 2 hours until completely set.
05 - Lift fudge from pan using parchment overhang. Cut into 36 squares. Store in airtight container in refrigerator for up to 2 weeks.