Line an 8 by 8-inch square baking pan with parchment paper, ensuring the edges overhang for easy removal later.

In a double boiler over medium-low heat, melt the white chocolate chips and vanilla frosting together, stirring occasionally for 8 to 10 minutes until creamy and smooth.

Divide the melted mixture evenly into three bowls. Color one bowl with red gel food coloring and another with green, leaving the third bowl plain white.

Dollop tablespoons of each color randomly into your prepared pan.

Use a butter knife to swirl the colors together, creating a marbled effect.

Refrigerate the fudge for 1 to 2 hours until set.

Once set, lift it out of the pan, let it sit for 20 minutes at room temperature, then slice into squares and serve.