Place cashews in lightly salted water and let soak for 4-8 hours (overnight is fine).
Drain the cashews and rinse well. Add to a blender (a high-speed blender is highly recommended) with the coconut milk, vanilla, and salt. Blend on high until as smooth as possible. Remove 1 cup / 250ml of this “marshmallow” mixture and set aside.
Place the dark chocolate (reserving a few pieces for garnish) in a small bowl. Brew the espresso, then immediately pour over the chocolate and stir well to melt. Add this and the dates and salt to the blender with the remaining marshmallow mixture still in it. Blend on high until completely smooth.
Place a couple spoonfuls of the mocha mixture in the bottom of dessert glasses or bowls. Then add a drizzle of the marshmallow to each glass, followed by more mocha, and lastly more marshmallow. Stir a little to get a swirl pattern. Crumble the graham crackers on top, sprinkle the remaining chocolate. Serve immediately for a looser texture, or place in the fridge until set – at least 4 hours. Say thank you and enjoy.