Levantine
Rinse the lentils, cover with 750 ml of the water, bring to a boil and simmer uncovered for 15-20 minutes until just tender but still holding their shape; do not drain.
Meanwhile, heat the olive oil in a wide frying pan and fry the onions over medium-high heat for 25-30 minutes, stirring often, until deep golden brown.
Rinse the rice and stir it into the lentils with the remaining 250 ml water, the cumin, salt, pepper and about a third of the fried onions with some of their oil.
Bring back to a boil, cover and cook over low heat for 18-20 minutes until the rice is tender and the liquid is absorbed.
Take the pan off the heat and let it rest, covered, for 10 minutes, then fluff with a fork.
Spoon onto a platter, top with the remaining crisp onions and drizzle over the rest of the onion oil.
Serve warm or at room temperature with plain yogurt or a tomato-cucumber salad.