Using a food processor, blend the mushrooms and walnuts until almost smooth, leaving some chunks. Set aside.
Fry off the onion and garlic, then add the tomato paste, spices, and fry off again.
Add the mushroom mixture, diced carrot, and fry off for a few minutes before adding the stock and simmering to reduce.
Add the cornflour towards the end to thicken the mixture, then set aside and allow to cool.
Cut your pitas into triangles, then stuff them with the mixture, rub a bit of oil on them, then bake/air fry or grill until crispy.
Serve with the tahini dip and enjoy!