If mint chocolate chips are not available, place 2 cups (12 ounces) semisweet chocolate chips and 1/4 teaspoon peppermint extract in a plastic bag; seal and toss to coat. Allow chips to stand for 24-48 hours.
One of the best things about this recipe is that the brownies get moister if you leave them in the refrigerator for a day or two. The problem at our house is no one can leave them alone for that long! —Helen Baines, Elkton, Maryland