For the honey simple syrup, combine 2 tbsp honey and 30ml water in a small saucepan. Heat over medium heat, stirring frequently, until it boils up slightly and the mixture is smooth. Remove from heat and let cool.
Combine Cointreau, lemon juice and the honey simple syrup in a cocktail shaker with some ice cubes. Shake vigorously for a couple of seconds.
Strain into two small glasses over ice. Garnish with fresh sprigs of rosemary if you like and serve.