Combine all ingredients in a bar glass, add ice and shake vigorously for 10 seconds. Pour over fresh ice into a 10-ounce rocks glass. Garnish with a wedge of fresh grapefruit. Makes 1 cocktail.
*Dice 8 stalks fresh rhubarb and combine with 1 cup sugar and 1 cup water in a saucepan. Bring to a boil, reduce to heat and simmer 20 minutes. Let cool completely before pouring it through a fine-mesh strainer into a clean bottle. Refrigerate up to 1 month.
Words by Willa Van Nostrand / Recipe by Lesley Bolton, Beverage Director, Avenue N American Kitchen, Rumford