Combine all ingredients in a cocktail shaker filled with ice. Shake and strain into a sugar rimmed glass. To prepare the sugar rim
rub the rim of your coupe with a lemon wedge and roll the edge in sugar until the rim is fully coated.
The Sidecar straddles that delicate line between sweet and sour. The drink is so similar to your typical "sour" formula but uses the sugar present in the Cointreau in lieu of simple syrup. This leaves the drink slightly on the drier side but rimming the glass with sugar lets you sweeten the drink as you desire and adds a wonderful tactile component to the drink.