Start by cooking the lentils. Pour lentils into a medium sauce pot and cover the lentils with water. Bring the water to a boil. Reduce the heat and let the lentil simmer for about 20 minutes. Drain extra liquid off before adding to the sauce.
Meanwhile, cook pasta according to directions. Drain when done and set aside.
While pasta and lentils cook, heat the oil in a large skillet over medium heat. Once oil is hot, add the finely chopped mushrooms, season with salt if desired and sauté 3 to 5 minutes or until mostly golden brown.
Add the cooked lentil and drained lentils to the skillet with mushrooms. Stir to combine. Add pasta sauce to the skillet next, again stirring to combine.
Taste sauce and season with salt if needed.
To serve, either spoon sauce over noodles, or add pasta to the sauce and toss to coat.
Top with grated cheese, fresh basil or red pepper flakes.