To prepare the pastry, sift the flour into a mixing bowl and add the ground almonds, arrowroot powder, flax, coconut sugar, cinnamon and salt. Mix well to combine.
Add the coconut oil and rub into the flour using your fingertips.
Add the water a little at a time and bring the mixture together with your hands to form a dough. Wrap the dough in baking paper and refrigerate for 10 minutes.
Preheat the oven to 180 degrees Celsius, 160 for fan assisted.
Remove the dough from the fridge and press into a large loose-bottomed tart tin – this can be rectangular or round. The one used for this recipe measures 14 x 5 inches. Ensure that the dough is of an even thickness on both the sides and base – about 5mm.
Prick the pastry base with a fork and transfer to the oven to bake for 10 minutes.
Whilst the pastry is baking, add the dates to a food processor with the cooked sweet potato flesh. Blend together until smooth.
Add the remaining filling ingredients and blend to a smooth, thick paste.
Spoon the filling evenly into the part cooked pastry base. Transfer back to the oven for 30 minutes to cook through.
Whilst the filling is cooking, add the topping ingredients to a small mixing bowl and stir together to combine.
Remove the pie from the oven and arrange the pecans over the top. Drizzle over the liquid from the pecan bowl.
Return to the oven for a further 10 minutes until the pecans are toasted and the topping has caramelised.