Place the chicken cubes in a pan, add the oil, onion, spices and stir over a low heat for 10 minutes with no colour.
Add the tomatoes along with their juice, the harissa, the coriander, cover with a litre of cold water, bring to the boil.
Reduce the heat, simmer for 25 minutes, before adding the 3 grains and chickpeas, simmer for further 15 minutes.
Add the broken vermicelli noodles, simmer for a final 5 minutes.
Stir in the egg and lemon mix using a large spoon to create egg strands in the soup.
Season with black pepper and serve.