Add all the ingredients for the crust to a food processor and blitz until you get a crust that easily sticks together but that still has some texture
Use your fingers to carefully press the mixture across the bottom and up the sides of a pie dish (I used a 22.5 cm/9 inch pie dish) - press down with your fingers, the back of a spoon or the bottom of a small cup or glass to make it as compact as possible
Place in the fridge while you make the rest
For the filling:
Cook the sweet potato by boiling, steaming or roasting
Discard any skins and add to the same food processor (no need to wash it) and whizz until completely smooth
Add the peanut butter, coconut yogurt and maple syrup and blend again until smooth
Taste and adjust amount of maple syrup if necessary
Place the filling in the crust and sprinkle over cacao nibs to decorate, if desired
Can be eaten immediately, but leaving it in the fridge for a few hours to firm up before cutting is advisable
Keeps well covered in the fridge for up to a few days