Wash the lentils and set them aside. Chop the onion, carrots, and celery into bite-sized pieces. Mince the garlic.

Heat olive oil in a large pot over medium heat. Add the chopped onion, carrots, and celery, stirring until softened, about 5 minutes.

Stir in the minced garlic, cumin, and turmeric. Cook for an additional minute until fragrant.

Add the rinsed lentils and vegetable broth. Bring to a gentle boil, then reduce to a simmer for 30-45 minutes, stirring occasionally.

Stir in optional coconut milk and red pepper flakes. Remove the bay leaf and adjust seasoning before serving.