Wash the lentils. Put them in a saucepan. Add 1 cup of water. Bring to a boil over high heat. Turn down the heat. Cook covered until all water is absorbed.
Wash the rice. Add it to the lentils. Salt. Add pepper. Add cumin and one cup of water. Mix gently. Bring to a boil. Turn down the heat. Cook covered until all water is absorbed. The lid will prevent the lentils and rice from sticking to the bottom of the pan.
Peel the onion. Wash it. Cut into slices.
Heat the olive oil in a pan. Fry the onion rings until golden brown. Remove. Add the boiling oil to the lentils after the water has been absorbed. Mix gently with a wooden spatula. Simmer for a few minutes until the oil is absorbed. Remove from heat. Let stand for a few minutes.
Serve decorated with fried onion rings. Serve with a tomato salad.