Prepare the Fudge

1. Melt the Chocolate: In a medium saucepan, combine the semisweet chocolate chips, white chocolate chips, sweetened condensed milk, and butter. Heat over medium-low heat, stirring constantly until the chocolate is fully melted and smooth.
2. Add Vanilla: Once the mixture is smooth, remove the saucepan from heat and stir in the vanilla extract.
3. Fold in Andes Mints: Gently fold in the chopped Andes mints, saving a few pieces to sprinkle on top for decoration.

Chill the Fudge

1. Transfer to Pan: Pour the fudge mixture into a greased 8×8-inch square baking dish or line it with parchment paper for easy removal.
2. Set the Fudge: Smooth the top with a spatula and sprinkle the remaining Andes mints on top.
3. Chill: Refrigerate the fudge for at least 2 hours, or until it’s firm enough to cut into squares.