Heat 1 tablespoon of the oil in a saucepan, add the onion and sauté gently for 5 minutes, until softened. Add the rice and stir for 1 minute until the grains become transparent, then add 2 cups of boiling water and a pinch of salt. Cover and cook gently for 18 minutes, or until the rice is tender.
Meanwhile, rinse the livers, pat dry on paper towels, then cut into small, even-sized pieces, removing any gristly bits. Heat the remaining oil in a non-stick frying pan, add the garlic, sauté for 1–2 minutes, then discard the garlic.
Add the livers to the oil and cook over a moderate heat for 3–4 minutes, turning regularly. Sprinkle with cumin, paprika and salt and pepper to season. Remove the livers to a dish.
Add the vinegar and 1½ tablespoons water to the frying pan and bring to the boil, scraping the bottom of the pan with a wooden spatula. Return the livers to the pan to keep warm in the juices, while serving the rice.
Drain the rice, if necessary, then heap it onto four serving plates. Top with the livers and pan juices and serve.
• Go to a butcher or chicken shop to buy chicken livers. When cooking, be careful not to cook them for longer than recommended in the recipe or they will become tough. • For a special occasion, try marinating the chicken livers for 1 hour in a couple of tablespoons of brandy with the leaves from 2 sprigs of fresh thyme. After cooking the livers in step 3, flambé them with the brandy.