Slice the avocado in half, remove the stone and use a spoon to scoop the flesh from the skin in one go. Slice in half again lengthways so you have a cavity on all 4 pieces for the eggs to sit. Set aside.
Grate the zucchini, garlic and lemon zest. Heat the olive oil in a large frying pan over a medium heat. Add the zucchini, garlic and lemon to the pan. Saute for a couple of minutes until tender.
Thinly slice the scallions. Add the scallions and spinach to the pan. Cover and leave to gently wilt for a few minutes.
Add the lemon juice, butter and creme fraiche (if using) to the pan. Stir into the zucchini and spinach mixture.
Carefully place the avocado quarters over the spinach mixture. Crack the eggs into the hollows. Cover and let the steam gently cook the eggs. Keep an eye on them as they can go from not-set to overcooked in an instant.
Season the shakshukado to taste. Roughly chop the dill. Crumble the feta and sprinkle the dill over the eggs. Add the final tablespoon of good quality olive oil over the top before serving.