Mint Chocolate Bark

. Line a cookie sheet with waxed paper; set it aside. Melt the semisweet chips in a heatproof bowl set atop a pot of simmering water over medium-high heat. Stir continuously until smooth. Pour the chocolate onto the cookie sheet and spread it to about a 1/4-inch thickness with the back of a spoon.

Using the same method, melt the white chocolate chips with the oil. Stir continuously until smooth. Add the peppermint extract and food coloring; stir well. Pour the mixture over the chocolate layer and spread to about a 1/8-inch thickness with the back of a spoon. Draw the tip of a butter knife through the layers to create swirls. Refrigerate until firm, about 30 minutes.

Remove the bark from the pan. Peel off the waxed paper. Set the bark on a cutting board and cut it into 2 dozen bars with a sharp knife. Store in an airtight container in the refrigerator.