1. Preheat oven to 325 deg F/160 deg Celsius.
2. Season chicken with salt and pepper. Mix together the buttermilk, cilantro, cinnamon, turmeric, cumin, ground coriander, masala and hot pepper. Pour over chicken pieces and marinate 3 hours or overnight.
3. Parboil rice in 2 cups water for 20 minutes, and drain well.
4. Simmer lentils in 2 cups water water for 20 minutes, and drain well.
5. Heat a fair amount of oil in a saucepan, and fry onion and potatoes until softened. Add the cinnamon, ground coriander, cardamom seeds, cumin and saffron (or sub with a good pinch turmeric) and cook, stirring, for a minute. Set aside.
6. Layer half the rice, followed by half each of of the lentils, and the spiced potatoes and onion in an ovenproof dish. Top with the chicken.
7. Repeat the layers with the remaining ingredients, top with saffron/turmeric water, and cover it all with tinfoil and a tight-fitting lid.
8. Bake for 1 1/2 - 2 hours or until chicken and rice are cooked through.
9. Garnish with quarters of hardboiled eggs and sprinkle with cilantro/coriander leaves.