Preheat oven to 200 degrees F. Line two large cookie sheets with parchment paper or foil; set aside. In a large bowl, combine egg whites, vanilla, cream of tartar, and salt. Beat with an electric mixer on medium speed until soft peaks form (tips curl). Gradually add sugar, about 1 tablespoon at a time, beating on high speed until stiff peaks form (tips stand straight). Gently stir in cocoa powder.

Transfer half of the meringue mixture to a pastry bag fitted with an open star tip. Pipe meringue in 3- to 4-inch-long sticks onto prepared cookie sheets. Repeat with remaining meringue mixture.

Place cookie sheets on separate racks in the preheated oven; bake for 1-1/2 to 2 hours or until meringues appear dry and are firm when lightly touched. Cool meringues completely on cookie sheets. Peel meringues off paper or foil.

In a small microwave-safe bowl, combine bittersweet chocolate and shortening. Microwave on 50 percent power (medium) for 2 to 2- 1/2 minutes or until chocolate is melted and smooth, stirring twice. Drizzle cookies with melted chocolate. Place cookies on waxed paper. Let stand until chocolate is set. Makes about 32 cookies.

Layer cookies between sheets of waxed paper in an airtight container; cover. Store at room temperature up to 4 days or freeze up to 3 months.