Finely dice the onion, carrot, and celery. Mince the garlic.
Add the olive oil, onion, celery and carrot to a large pot. Sauté the vegetables for about 5 minutes over a medium until the onions are translucent and the vegetables have softened.
Once vegetables have softened, add the minced garlic, crushed red pepper and walnuts to the pot. Saute for 2 minutes over medium-low heat, or until the garlic is fragrant.
Add the lentils, crushed tomatoes, tomato paste, dried oregano, dried basil, garlic powder, salt, sugar, pepper, and vegetable broth to the pot. Mix everything together and bring the sauce to a boil.
Reduce the heat to low and simmer, semi covered with a lid, stirring occasionally for 20-25 minutes. After about 25 minutes the lentils should be soft and the sauce thickened. If the sauce is still too thin for your liking, continue simmering until it has reached your desired consistency.
Once the bolognese has reached your desired consistency and texture, stir in the coconut milk and simmer for another 5 minutes. Taste the bolognese and add salt to taste. Turn off the heat. The bolognese will continue to thicken as it cools.
*The walnuts add a nice richness to the sauce. You can also use pecans or cashews if you can't have walnuts. Or, you can leave them out altogether if desired.**You'll want to use red lentils for this recipe because they break down quickly, helping the sauce thicken up and get extra rich. They'll retain just enough texture to feel "meaty" without looking like lentils. The red/orange color of the cooked lentils also helps the sauce retain a nice deep red/brown color. Green/brown lentils will also work, but they hold their shape better than red lentils, meaning the sauce will be chunkier and not as thick.***Full-fat canned coconut milk adds a subtle creaminess, and I promise it won't make your lentil bolognese test like coconuts! If you're not making this recipe dairy-free or vegan, you can use whole milk, half and half, or a splash of heavy cream in place of the coconut milk. You can also omit it altogether for a non-creamy sauce.