A riff on the drink called the Monarch - we replaced the lemon juice with grapefruit and left out the sugar.
2 oz Tanqueray gin
3/4 oz St. Germaine elderflower liqueur
1 oz grapefruit juice
4 mint leaves
Twist of lemon
Tear the mint leaves into a shaker and add the gin, liqueur and juice. Shake with ice and double strain into a cocktail glass. Add twist and mint leaf to garnish.
Optional: Add to Collins glass with ice and top off with club soda. The first went down too quickly we wanted the second one to last!