To make the spicy aioli, mix together the aioli, harissa and preserved lemon. Set aside until needed.
Blitz the pistachios to a fine crumb in a food processor. transfer to a shallow bowl, add the almond meal, parsley, chilli flakes (if using), garlic powder, onion powder, a pinch each of salt and pepper and mix well.
Place the eggs and coconut cream or almond milk in a shallow bowl and whisk well. Place the tapioca flour in another shallow bowl.
One by one dust the chicken strips in the tapioca flour, shake off any excess flour, dip in egg mixture and then coat in the nut crumb mixture, making sure you cover the entire chicken strip thoroughly. If there are areas that are not entirely coated, simply dab a little more egg mixture onto the dry spot and coat again with the nut crumbs.
Heat the oil or fat in a large frying pan over medium-high heat. Add the crumbed chicken strips, in batches, and cook for 2½-3 minutes on each side until golden brown and cooked through. Drain on paper towel. Allow to cool slightly before serving. Season with salt, if needed.
Serve the pistachio-crusted chicken with the spicy aioli and some lemon cheeks on the side.