Peel and grate or crush the garlic. Grate or pare the zest from the lemon. Juice it. Cut each chicken fillet into 3-4 pieces. Pop in a non-metallic bowl.
Add the garlic, lemon zest and juice, 1 tsp of the cumin and a pinch of cayenne (it’s spicy, so add to taste). Season. Mix well. Cover with a saucer. Put to one side to marinate for 10 mins.
While the chicken marinates, peel and finely chop the onion. Halve the pepper. Scoop out the seeds and white bits. Roughly chop it.
Halve the squash. Scoop out the seeds. Slice or peel off the skin. Chop the squash into chunks around 2 cm big.
Heat ½ tbsp of oil in a wok or deep frying pan. Add the chicken. Fry over a medium heat for 4-5 mins till golden brown all over. Add the onion and pepper. Stir and fry for another 5 mins till the veg look glossy.
Add 150 ml boiling water to the pan with the chopped tomatoes and squash. Bring to the boil. Cover. Simmer for 15 mins till the squash is tender and the chicken is cooked through.
Strip the parsley leaves from the stalks and finely chop them. Taste and add more salt, pepper or cayenne if you think it needs it. Serve the stew topped with spoonfuls of the yogurt and chopped parsley.