Heat the 3tbsp oil in a saucepan over moderate heat.
Add the 1 finely chopped onion and zest and fry gently without browning for 5 minutes.
Add the rice and mix well.
Add the stock and bring to the boil, cover tightly then turn the heat down to the lowest setting and cook for 20 minutes without uncovering.
Once Rice is cooked uncover, fluff up the rice with a fork then add the hot peas and butter.
Season and mix well without mashing the rice. Cover and let stand 3 minutes.
While rice is cooking start on your casserole by heating 3tbsp oil over moderate heat. Add the other chopped onion, garlic, carrots, cumin seeds, chilli and sausages and fry gently for 10 minutes until the onion is soft and the sausages browned.
Add the tomatoes and 3/4 cup water, bring to the boil and then simmer for 10 minutes until thick.
Taste, season and serve with rice and some steamed broccoli.