Again stolen from Stanley Tucci from his wonderful book, "Taste".
This is cheap, filling, vegetarian, takes about 30 minutes, and is infinitely variable. The end result is tasty, but nothing amazing. Just a solid meal that is good to make and take to work for lunch or a "meatless Monday". You can add meat, or a meat sauce, mushrooms, different kinds of pasta, chili flakes, whatever...this is just a good base for a dish.
Lentil and Spaghetti dish. 1/2 onion 1/2 carrot 1/2 celery stick a couple of garlic cloves 3 T olive oil 1 cup of dried lentils 1 1/2 cups of your favorite spaghetti sauce 1 cup of spaghetti, broken up into 1" pieces Salt and Pepper Parmesan cheese Fresh basil, olive oil, or whatever you like to finish with.
3 pots. One should be big enough to hold everything.
Rinse lentils and put in a medium pot. Add water to cover by about an inch. Put on the fire and bring up to a simmer, cover and simmer about 20 minutes.
In another pot, bring several cups of water to a boil, add a bit of salt and add pasta. Bring to a boil and boil until tender.
While those are cooking, chop onion, carrot, celery, and garlic finely. (I added some mushroom because I like mushroom). In third pot, (the one that will hold everything) heat over medium high heat and add olive oil. Warm up then add the chopped vegetables. Saute' until tender, about 7 - 10 minutes. Add the spaghetti sauce. Bring to a simmer and keep warm.
Once the lentils and pasta are done, reserve 1/4 cup of the pasta water and drain the rest. Add to the pot with the spaghetti sauce. Add the reserved pasta water and bring heat to medium. Stir until things mingle and thicken. Add a metric butt-ton of grated parmesan cheese. Salt and pepper to taste.
Garnish with a drizzle of oil, fresh parsley or basil, or whatever you want.
Change up the recipe as you wish. Add macaroni or egg noodles. Add shredded chicken. Use meat sauce instead of marinara. Add zucchini. Hey, I won't judge.