Bring 1/2 cup water to boil in a small saucepan.
Add Earl Grey tea leaves to brew for 4 minutes.
Add sugar and stir to dissolve.
Strain syrup into measuring cup. Set aside to cool.
Fill a cocktail shaker with ice. Add Grand Marnier, Earl Grey Syrup, and lemon juice. Shake well.
This recipe scales equally to the number of servings required. Just multiply the ingredients by the number of servings needed.