Sweet Potato Lentil Stew

This is originally from Fix-It and Forget-It Lightly - I've changed a few things. :)

4 c. vegetable or chicken broth
3 c. sweet potatoes, peeled and cubed
1 ½ c. lentils, rinsed
3 med. sized carrots, chopped
1 med. onion, chopped
½ c. celery, chopped (opt.)
4 garlic cloves, minced
1 - 1 ½ tsp. ground cumin
1/2 tsp. ground ginger
¼ tsp. cayenne pepper
1-2 tsp. salt
¼ - 1/2 c. minced fresh cilantro or parsley
Shredded Monterey Jack (opt.)

Combine the first eleven ingredients in slow cooker. Cook on low 5-6 hours or just until vegetables are tender. Stir in cilantro just before serving. Top with shredded monterey jack if desired.