1. Preheat oven to 350 degrees F. Line two baking sheets with parchment paper.
2. In large bowl of an electric mixer, beat butter and brown sugar on medium speed until blended, 1 minute. Using a rubber spatula, scrape down sides and bottom of bowl and beaters as needed. Add egg and vanilla, and mix until blended, about 30 seconds.
3. Sift together flour, cocoa, baking soda, and salt, and add to mixer bowl. Mix on low speed just to incorporate, about 30 seconds.
4. Using a large spoon, stir in chocolate chips and crushed peppermint candy, distributing evenly.
5. Drop rounded tablespoons of dough onto baking sheets, leaving about 3 inches between cookies.
6. Bake for about 12 to 15 minutes, until cookie edges are light brown. Let sit 5 minutes on baking sheets. Remove cookies to wire rack to cool.
7. Store in a tightly sealed container at room temperature for up to two days.
Source: Hannaford fresh Magazine, November - December 2006