Add the olive oil to a large saucepan or Dutch oven over medium heat.
Once the olive oil is hot, add the onion and cook for about 5 minutes, or until translucent and slightly caramelized.
Add the garlic, Italian seasoning, salt, pepper and red pepper flakes, if using. Cook for 2 additional minutes before adding the lentils, crushed tomatoes, and tomato sauce.
Bring the sauce to a boil and then reduce the heat to low. Cover and cook for at least 20 minutes.
Serve with pasta or veggie noodles of choice.
Tips
BIG thank you to my friend Allie from Miss Allie’s Kitchen for creating this delicious recipe and taking these gorgeous images for us!! I love her work and couldn’t be more excited she’s creating some tasty dishes to share here too!