In a large pot over medium heat, add the water, onion, potatoes, celery, carrots (if using), garlic, dried herbs and spices, salt, and pepper.
Stir through, cover, and cook for 6-8 minutes, stirring occasionally.
If veggies are sticking, add another splash of water.
Add the lentils, stir through, cover and cook for another few minutes, and then add the vegetable stock, water, miso, molasses, bay leaves and stir through.
Increase heat to bring to a boil, then reduce heat to medium-low, cover and let cook for 30- 40 minutes, until the lentils are very soft and fully cooked. (If using the chopped red pepper, add after first 25-30 minutes of cooking lentils, see note).
Turn off heat, add the cannellini beans (see note), kale, stir through, cover, and let wilt in soup for about 5 minutes.
Remove bay leaves to serve, and taste to add additional salt and pepper if desired.