For extra flavor, try using smoked sausage or adding a splash of red wine when cooking the vegetables. You can swap kale for spinach, Swiss chard, or collard greens depending on your preference. This soup stores well in the refrigerator for up to 4 days and also freezes beautifully for up to 3 months. When reheating, add a little broth or water if the soup has thickened too much. For a vegetarian version, omit the sausage and add extra vegetables or a smoky seasoning to keep the depth of flavor.