To a small saucepan, set over medium-low heat, mix together the blackberries, water, sugar, ginger and salt. Cover the pan and cook until the blackberries have softened and have begun to release some of their juices, about 5 to 7 minutes. Using a fork, mash the blackberries (be careful—it can get messy!). Run the syrup through a sieve (you should end up with about 3 tablespoons of syrup left). Set aside to cool. 

Preheat the oven to 350 degrees F. Line a baking sheet with parchment. In a small bowl, whisk together the all-purpose flour, brown sugar, baking powder, ginger, cinnamon and salt. Mix the cubed cold butter into the flour mixture, until it resembles the size of large peas. Spread the crumble onto the baking sheet and bake for about 8 minutes, until lightly golden brown. Remove and allow to cool completely on the baking sheet. 

To a blender, add the almond milk and ice cream. (Depending on how big your blender is, you may need to do this in batches.) Pulse for about 5 seconds. Seriously you don’t want it too runny! I have a Vitamix and just did like little pulses until the ice cream was broken up a bit. 

To assemble: Fill each of the cups about 1/4 of the way. Drizzle in a teaspoon or two of syrup. Pour in more of the vanilla milkshake. And then drizzle more syrup in. Top with the last bit of the milkshake and pour in a final drizzle of syrup; finish the milkshakes with a handful of the crumble topping.