Signature Drink: Strawberry Shrub Martini

INGREDIENTS
—.5 oz. strawberry shrub*
—1.5 oz. Kettle One Vodka
—1.5 oz. lemon juice
—.5 oz. simple syrup
—3 oz. fever tree soda
FOR STRAWBERRY SHRUB
—2 cups strawberries
—hulled and sliced
—2 cups granulated sugar
—1 cup cider vinegar
—1/2 cup white wine vinegar