Prepare your workspace: Line an 8-inch square baking dish with parchment paper and lightly grease it.
Combine ingredients: In a medium saucepan, combine the chocolate chips, sweetened condensed milk, unsalted butter, and a pinch of salt. Heat over low, stirring until melted and smooth.
Add Baileys and vanilla: Remove from heat and stir in Baileys and vanilla extract until well combined.
Pour into prepared pan: Pour the mixture into the baking dish and spread evenly.
Add toppings: Sprinkle optional toppings over the fudge while warm.
Chill until set: Refrigerate for at least 2 hours or until firm.
Cut and serve: Lift the fudge out of the pan and cut into squares.
Notes
Store the fudge in an airtight container in the refrigerator for up to two weeks.