1 cup butter, softened
3/4 cup granulated sugar
1 tsp vanilla
1 3/4 cup all-purpose flour
2/3 cup cocoa powder
1/2 tsp baking powder
6 oz bittersweet chocolate, chopped
1/3 cup whipping cream
1/2 cup chocolate sprinkles
Line 2 rimless baking sheets with parchment paper or grease; set aside.
In large bowl, beat butter with sugar until fluffy; beat in egg and vanilla.
In separate bowl, whisk flour, cocoa powder, baking powder and salt; stir into butter mixture in 2 additions. Divide in half; flatten into squares. Wrap each and refrigerate until firm, about 30 minutes.
On floured surface, roll out each half of the dough into 10-inch (25 cm) square. Cut into 4 strips; cut across strips at 1-inch (2.5 cm) intervals to make 40 pieces. Place 1 inch apart, on prepared pans. Refrigerate until firm, about 30 minutes.
Bake in top and bottom thirds of 350 F oven, rotating and switching pans halfway through, until edges begin to darken, 8 minutes. Transfer to racks; let cool. (Make Ahead: Store layered between waxed paper in airtight container for up to 1 week or freeze for 1 month.)
Place chocolate in heatproof bowl. In saucepan, bring cream to boil; stir into chocolate until melted. Spread 1 tsp onto half the cookies. Top with remaining cookies; press to reveal filling. Dip 1 end of the cookie into chocolate then into sprinkles. Let harden on rack. Makes 40 cookies.
Source: Canadian Living Holiday Celebrations, 2007