Heat the oil large pan over medium heat. Add the onion and 1/2 teaspoon each salt and pepper.
Place the garlic, mushrooms and carrots to the base of a food processor and chop until very well chopped. This gives the vegetables the texture of meat. If you don't have a food processor, finely chop instead. Add the vegetables to the onions and cook until reduced and browned, about 8 minutes.
Add in the umami powder, if using, basil, oregano, red pepper flakes and sugar. Cook another 1-2 minutes, then add in the red wine. Cook until reduced by half, about 5 minutes.
Stir in the lentils and tomatoes and simmer another 20-30 minutes until thickened. Right before serving, stir in the balsamic vinegar.
When ready to enjoy, bring a large pot of salted water to a boil and add the rigatoni. Cook until just under al dente. Toss with the cooked lentil sauce and handful of fresh basil. Off heat, stir in the parm cheese, if using. Season to taste and serve.
Notes
* I use the umami powder from Trader Joe's and find it gives a nice umami hit of flavor to the sauce. If you don't have it, you can substitute dried porcini powder or omit.** I typically don't add in any sugar to my tomato sauce recipes, but find that this recipe benefits from a little sweet balance to enhance the tomato taste.***Canned lentils are best in this recipe, but if you can't find them then substitute 1 1/2 cups cooked brown lentils.