Begin by placing a medium saucepan over low heat. Add the sweetened condensed milk and white chocolate chips, stirring continuously until the mixture is completely melted and smooth, about 5–7 minutes. For a festive touch, add drops of red food coloring and mix until fully combined.

Remove the saucepan from heat. Stir in the peppermint extract and half of the crushed peppermint candies until well incorporated.

Pour the peppermint-infused white chocolate mixture into a greased or parchment-lined 8x8-inch square pan, spreading it evenly.

Melt the semi-sweet chocolate chips in the same saucepan, stirring until smooth. Dollop this over the white chocolate base and gently swirl together with a toothpick or knife.

Sprinkle the remaining crushed peppermint candies over the fudge, pressing lightly to ensure they adhere.

Refrigerate for at least 3 hours or until firm. Remove from the pan and cut into squares.