slow cooker lentils sloppy joe

My colleague and author of the blog Wholesome Heart sent this to me and we loved it...especially Sam.  It was so easy to prepare, as most slow cooker recipes are.  Packed full of protein (even without the meat) as well as fiber, B vitamins including folic acid, iron, magnesium, Vitamin A etc etc, this recipe can't be beat for nutritional and economical value. 

1 onion, sliced
1 red pepper, sliced
2 stalks of celery, chopped
1.5 T chili powder
1.5 cups brown or green lentils
3 cups cherry tomatoes diced or 1 14.5 oz can of diced or crushed tomatoes
2 cups water
2 T soy sauce
1 T prepared mustard (Dijon or yellow)
2 T maple syrup
1 t salt
pepper
Optional: 2 t. cumin, 1 t. ground ginger

Saute onion in oil until soft (about 5 minutes). Put in crock pot and add everything else, cook on low for 5 to 6 hours.
Enjoy!