Combine : In the basin of a 4. 5- to 5-quart slow cooker, combine the pasta sauce, vegetable broth, and water.
Stir well to create the sauce base.
Add Vegetables and Lentils: Stir in the rinsed lentils, chopped carrots, celery, onion, and crushed red pepper flakes until everything is evenly distributed and submerged in the liquid.
Slow Cook: Secure the lid and cook on the low-heat setting for 12 to 14 hours or on the high-heat setting for 6 to 7 hours, until the lentils are tender and the sauce has thickened.
Serve: Serve the rich lentil bolognese generously over hot cooked penne pasta. If desired, finish with a sprinkle of vegan Parmesan cheese.
Stir in a handful of fresh, chopped herbs like basil or parsley right before serving to brighten up the flavors of the slow-simmered sauce.