Similar to French cookies called sablés, these have a slightly sandy texture and rich flavour.
Ingredients
9 tbsp (125 mL) unsalted butter, softened
⅔ cup (150 mL) granulated sugar
1 tsp (5 mL) vanilla
1 cup (250 mL) all-purpose flour
⅓ cup (75 mL) cocoa powder
½ tsp (2 mL) baking powder
¼ tsp (1 mL) kosher salt
3 oz (85 g) bittersweet chocolate, cut in small chunks
Preparation
In bowl, cream butter with sugar; beat in vanilla. Whisk flour, cocoa powder, baking powder and salt; then stir in butter mixture in 2 additions. Stir in chocolate to make crumbly dough.

On plastic wrap, form dough into 1½" (4 cm) diameter log; wrap in plastic wrap and chill for 1-2 hours.

Slice log into ½" (1 cm) thick rounds. Place, 1" (2.5 cm) apart on a baking sheet.

Bake, 1 sheet at a time, in 325ºF (160ºC) oven until edges are dry but centre is still a bit moist, about 12 minutes. Let cool on pan on rack for 5 minutes. Transfer to rack & let cool completely. (Store in airtight container for up to 1 week or freeze for up to 1 month.)