In a large stock pot, pour in the 10 cups of water, and place on the stove over high heat. Place the lid onto the pot, so that it comes to a boil more quickly. In a separate deep sided pot with a tight-fitting lid, heat the stock over high heat.
Mince your onions. Open up the can of tomatoes and lentils. Do not drain the cans of their extra liquid! In a large, shallow skillet, heat the olive oil over high heat. When the oil gets hot, add the onions, and a healthy sprinkle of salt and pepper. Let cook over high heat for about five minutes, or until soft. Turn down the heat to medium, and add the canned tomato and lentils.
By now, the stock should be boiling. Add the rice to the pot, and wait for the stock to come up to a full boil (uncovered). When the water is boiling vigorously, turn down the heat to a simmer, and cover the lid. Give the skillet with the tomatoes a quick stir.
By now, the ten cups of water should be boiling. Liberally salt the water, and add the macaroni to the pot. Leave the lid off, and allow the macaroni to cook fully according to your liking.
The rice should take a total of twenty minutes to cook. The macarnoi should take no longer than ten minutes to cook. By the time the rice and macaroni are cooked through, the sauce will be the perfect consistency. If it looks a little too loose for your liking, turn up the heat to high, and allow it to cook down for a few minutes.
Drain the pasta, and put it back into the large pot. Stir in the sauce. Stir in the cooked rice. Generously garnish with the chopped parsley.
*This is the perfect dish to use up leftover pasta and rice. It doesn't even matter what kind of pasta you use! You can use elbow macaroni, spaghetti, or linguine, and still come out with fine results.
Another variation is to use jarred tomato sauce. This way, all you have to do is brown the onions in the oil, and just stir everything together at the end. I like the texture of the sauce, however, because I feel that it stays together better than when you use jarred sauce. It also doesn't take that much extra time.