Slow Cooker Lentil Soup with Baked Sweet Potato

dry brown or green lentils

chopped Vidalia or Spanish onion

stalks of celery (chopped)

carrots (chopped)

garlic (crushed)

low sodium vegetable broth ((I prefer the Pacific organic brand))

bay leaves

dried thyme

ground black pepper

packed baby spinach ((or other chopped dark leafy greens))

salt ((or to taste*))

large sweet potatoes or yams