Add everything (but the spinach, lemon, and cilantro) to the crock pot. Cover and cook on low for 6-8 hours or high for 4 hours, until the lentils are soft.
Cover and cook on low for 6-8 hours or high for 4 hours, until the lentils are soft.
Stir in the baby spinach and the lemon juice.
Cover and cook for 10 minutes.
Serve with fresh cliantro on top.
