To make the biscuit, place the pecans, dates, salt, vanilla and cacao in a food processor and blend until the mixture has a dough-like consistency.
Roll the mixture into a large ball and place it on a cutting board. Using a rolling pin, flatten it out to about 5 mm (¼ inch) thick.
Cut out eight circle shapes, using an 8 cm (3¼ inch) cookie cutter. Refrigerate for 2-3 hours, or until firm. (To speed things up,
you can freeze the cookie rounds for about 1 hour.)
Clean out the food processor.
To make the filling, drain the cashews and place in the processor. Add the remaining filling ingredients and blitz until creamy and smooth.
Spread the filling over half the chilled cookies. Top with the remaining cookie halves and sandwich them together.
The cookies will keep in an airtight container in the fridge for 7 days, or in the freezer for 6-8 weeks.