Blackberries – fresh berries and some for garnish.
Mint leaves – go for fresh so the oils come out when muddling.
Blackberry Soda – adjust amount to taste.
Agave nectar – or you can use honey.
Muddle blackberries and mint leaves with lime juice and honey. Then add grapefruit juice and tequila. shake well. Top with blackberry soda and serve with garnish.