Add the gelatin to a small dish and cover with the water and allow to soften. 

In a small saucepan set over medium-high, add the buttermilk, cream and milk. Heat just until there are bubbles along the edges, add the sugar and stir until dissolved. 

Remove from the heat. Set the gelatin into the microwave and zap it for 10 seconds or until it is syrupy. Add the gelatin to the buttermilk mixture and stir to incorporate completely. 

Pour the mixture through a fine-mesh strainer into another bowl and transfer to the refrigerator for about 30 minutes to cool and slightly thicken. 

Stir the mixture and pour into four 6-ounce custard dishes or molds. Transfer to the refrigerator and chill for 2-3 hours until firmly set. 

To a medium-size saucepan, add the blackberries, wine, sugar, vanilla and star anise. Bring to a boil then reduce the heat to simmer and cook for about 15 minutes. Remove from the heat and allow to cool, then remove and discard the star anise and transfer the blackberry mixture to a blender or food processor and process until smooth. 

Pour through a fine-mesh strainer to remove and discard the blackberry seeds. Stir in the blackberry liqueur if using. Transfer the sauce to a bowl or pitcher, cover with plastic wrap and chill. The sauce will be slightly thickened after it has cooled.

Run the tip of a thin knife around the rim of each custard and tip the custards into the center of four chilled shallow dishes.  

Carefully pour or spoon the sauce around each of the custards. Garnish with fresh blackberries and sprigs of mint.