In your food processor, process the hazelnuts until nicely ground. It won’t be as finely ground as store-bought almond meal, but a little coarser. Don’t process too long or you’ll have hazelnut butter. It shouldn’t take any more than 20 seconds. Add the dates, cocoa powder, maple syrup and vanilla and process until a sticky dough forms.
Place the dough between two Silpats or pieces of parchment paper and roll out to about 1/4 of an inch thick (or really, however thick you want it). Cut them however you like (I used 1 1/2″ circular cookie cutters) and form the excess dough into a ball, roll out again and cut out more shapes.
For the frosting, in the bowl of your food processor, combine all the ingredients until thoroughly combined and no chunks of avocado are left. It took me a few minutes to do this but it was possible. If it’s not sweet enough, add more maple syrup.
The espresso flavor was really light even with quite a bit of powder, but I still liked the difference it made. Add the frosting to the cake and store in the fridge.