Season the chicken pieces with salt and pepper. Crush the cumin and coriander seeds using a mortar and pestle.
Heat the oil in a frying pan on the hob and gently fry the chicken for 5 minutes, stirring, until beginning to colour. Stir in the garlic, onions and crushed spices. Fry gently for a further 3 minutes, stirring.
Turn into a casserole dish and add the lentils. Bring the tomatoes, tomato paste, sugar and chicken stock to the boil in the frying pan and pour over the chicken and lentils. Mix the ingredients to combine and season with salt and pepper. Cover the dish with foil and place on the lower rack of the halogen oven.
Set the temperature to 200°C (392°F) and cook for about 40 minutes until the chicken is cooked through. Serve the dish with warm flat breads and a roasted tomato salad.