Process the nuts and dates in a food processor until finely ground. Add the cacao powder, honey, almond butter, vanilla extract and a pinch of sea salt, and process until well combined.
Using your fingers press the dough in the tart pans, pressing it up the sides of the pans. Place the pans in the fridge while you are making the filling.
Filing
Combine together cacao powder, honey, coconut oil and water in a medium pan. Heat over medium high heat until coconut oil is melted and ingredients are well combined.
Grind finely cashews in a food processor and add to the chocolate filling mixture. Add orange zest and orange juice and mix well.
Pour filling over crust. Refrigerate for about 1 hour.
Top chocolate tarts with berries and ground pistachios.