*To prepare the gomme syrup, pour 7 oz of brown sugar and 6.7 fl oz (4/5 cup) of water in a small pot. Stir until it boils and allow to cool.
Cut the lemon into four pieces and put in a glass together with the blackberries and basil. Gently tenderize with a mortar.
Add the gomme syrup and correct sweetness to taste.
Fill the glass with crushed ice or ice cubes and add the mezcal. Stir and serve with a straw.
Decorate with a few blackberries on the side.
