01 - Line an 8x8-inch baking pan with parchment paper, allowing an overhang for effortless release.
02 - In a medium saucepan set over low heat, gently combine white chocolate chips, sweetened condensed milk, and unsalted butter, stirring continuously until the mixture is completely smooth and melted.
03 - Remove the saucepan from heat; blend in vanilla extract and a pinch of salt until incorporated.
04 - Transfer the warm fudge evenly into three heatproof bowls.
05 - Leave the first bowl plain for the white layer. Tint the second bowl with a few drops of orange gel coloring, stirring until consistent. Tint the third with yellow gel coloring and stir until uniform.
06 - Spread the yellow fudge evenly on the bottom of the prepared pan. Carefully layer the orange fudge over the yellow, then spread the white fudge on top of the orange.
07 - Using a skewer or butter knife, gently swirl the layers together for a marbled visual, taking care to avoid overmixing.
08 - If desired, immediately sprinkle chopped candy corn over the surface and lightly press into the fudge.
09 - Refrigerate the pan for at least 2 hours or until the fudge is fully set.
10 - Lift out the fudge using the parchment overhang and cut it into 36 square pieces before serving.