Combine chopped sweet potatoes, onion, garlic, ancho chile powder, salt and cayenne in the base of slow cooker. Stir well to coat the potatoes with spices.
Pour in chicken broth and add the bay leaf. Cover and cook on low for 6 hours.
Remove the bay leaf and use a handheld immersion blender to puree until smooth. If you don’t have an immersion blender you can puree the soup, in batches, in a regular blender.
Stir in the lime juice, and serve garnished with fresh chopped cilantro, pomegranate seeds, and crumbled queso fresco.