1. CENTER a rack in the oven and preheat the oven to 325°F. Generously butter a 9×13 glass baking pan.
2. PLACE butter in a microwave safe bowl; top with the chopped chocolate. Microwave for 45 seconds, then remove and stir vigorously with a whisk until the ingredients are just melted (you don’t want them to get so hot that the butter separates). Microwave for another 30 seconds if needed to melt the chocolate completely.
3. WHISK in the sugar. Whisk in the eggs one by one. Add the vanilla and peppermint extracts and whisk vigorously to bring the batter together and give it a shine before gently stirring in the salt and flour; stir only until incorporated. Switch to a rubber spatula and fold in 2 cups of the candy cane pieces. Scrape the batter into the pan and smooth the top with the rubber spatula.
4. BAKE the brownies for 30 to 33 minutes, or until the top is dull and a thin knife inserted into the center comes out clean. (The tip of the knife may be a touch streaky.) Transfer the pan to a rack and cool to room temperature.
5. MAKE the ganache while the cookies are cooling. Place chopped chocolate in a medium bowl. Bring heavy cream to a boil. Once heavy cream has reached boiling, pour half the heavy cream over the chopped chocolate. Let sit for 30 seconds, then gently stir chocolate and cream together with a rubber spatula in a figure eight motion. Pour remaining heavy cream over chocolate and continue to gently stir. Add butter, one piece at a time, until ingredients are fully incorporated and ganache is smooth and glossy.
6. POUR ganache over brownies and smooth with rubber spatula to completely cover top of brownies. Sprinkle remaining 1/2 cup of crushed candy canes on top of ganache.
7. REFRIGERATE brownies for one hour until ganache has set before cutting into squares.