2/3 cup flour
2 tablespoons dark or dutch processed cocoa powder
1/2 teaspoon salt
4 ounces semisweet baking chocolate, chopped
4 ounces unsweetened baking chocolate, chopped
1/2 cup (1 stick) unsalted butter, cut into cubes
3/4 cup granulated sugar
2 large eggs, at room temperature, lightly beaten
3/4 teaspoon vanilla extract
1/4 teaspoon peppermint extract

For Topping:
6 ounces good quality white chocolate, chopped
1 1/2 tablespoons vegetable shortening
3 to 4 candy canes, coarsely chopped or crushed (about 1/2 cup)