1) Fill a cocktail shaker with ice. Add the vodka, lingonberry concentrate, and bitters. Cover and shake vigorously until thoroughly mixed and chilled, about 30 seconds. (In general, the drink is ready by the time the shaker mists up.)
2) Strain into a chilled cocktail glass. Top with the orange and grapefruit juices. Garnish cocktail with citrus. Drink.
Note: Look for lingonberry concentrate at specialty stores, or stores that feature Scandinavian products.