Line a large cookie sheet with waxed paper; set aside. In a small saucepan cook and stir chocolate coating and bittersweet chocolate over low heat until melted. Remove from heat.
Using two forks, dip each sandwich cookie into chocolate mixture to coat, allowing excess coating to drip back into pan. Place coated cookies on the prepared cookie sheet. Top with sprinkles. Let stand until coating is set.
Place cookies in layers separated by waxed paper in an airtight container; cover. Store at room temperature for up to 3 days.