Add all ingredients into a shaker with ice and shake until well-chilled.
Double-strain into a chilled coupe.
Express the oil from a lemon peel on top, then discard peel.
*Earl Grey syrup: Brew 1 Earl Grey tea bag in 1 cup almost-boiling water according to package directions. Add 1 cup sugar while tea is still hot, and stir to combine. Store tightly covered in the refrigerator for up to 1 month. Discard if it becomes cloudy.