Pour milk into a medium bowl. Sprinkle gelatin over and let sit for 10 minutes, until gelatin softens.
Add the cream and sugar to a saucepan. Slowly heat the mixture until the sugar dissolves, then turn off the heat. Add chocolate chips and milk/gelatin mixture and stir carefully until the chocolate is completely melted.
Strain the mixture into two serving glasses and place in the fridge to set for 3 hours.
Just before serving, garnish with blackberries and fresh mint leaves.