Sausage, Kale, and Sweet Potato Soup
1 (15 ounce) can diced tomatoes, undrained 1 (15 ounce) can great northern beans, draine… 1 bay leaf 1 large yellow onion, chopped 1 tablespoon olive oil 1 teaspoon salt 2 stalks celery, thinly sliced 3 cups cubed sweet potato 4 cloves garlic, minced 5 cups chicken broth 5 cups chopped kale, or to taste 8 ounces hot Italian sausage, casings removed 8 ounces mild Italian sausage, casings remove… ½ teaspoon ground black pepper