Combine the sugar and lemon juice in a small saucepan and bring to a boil. Stir until the sugar dissolves and the mixture becomes thick like syrup. Remove from the heat and cool. Fill two glasses with crushed ice. Pour one-half cup of the Lillet in each glass and a tablespoon or two of the lemon syrup into the glass. Top off the drinks with a splash of club soda. Garnish with the lemon slices.
Makes 2 drinks