To make the pie crust, put the almonds, salt and allspice in the bowl of a food processor. Process until finely ground and loose. Add the raisins, agave nectar, vanilla and 1 tbsp cold water and process until the mixture begins to stick together to form coarse crumbs.

Put the mixture in the dish/pie plate and distribute along the bottom and the sides to form and even layer. Press to compact with your hands, shaping the crust flush with the rim. (The pie crust should be about 8mm / 3/8in thick.) Chill in the refrigerator for 20 minutes.

To make the filling, put 250g / 2 cups of the blackberries, the dates, agave nectar and lemon juice in the bowl of a food processor and process until smooth. Transfer to a large bowl and stir in the remaining blackberries.

Pour the filling into the pie crust and distribute evenly with a spatula. Refrigerate for two hours then cut into slices and serve chilled with Greek yogurt on the side, if liked.