Wash and sort the lentils and cook until they are tender but firm (cover with water in a 3 to 1 ratio). Bring to a boil, then lower the heat and simmer until tender, about 40 minutes or so. Saute the garlic in scant bit of water for a minute or so.
When the lentils are done, add the garlic and all the remaining ingredients. Cover and simmer over very low heat for 15 minutes. Now, add the spinach leaves, cover and let steam until they are wilted.
Serve over brown rice, couscous or mashed potatoes.