In a large saucepan on medium heat, cook the onion and kale stem slices in 1 tsp olive oil with a generous pinch of salt for about 5 min, stirring occasionally.
Add celery and carrots, cook 3 more min.
Add zucchini and red pepper, cook 2 min.
Add garlic, thyme, and oregano. Stir and cook 30 sec.
Add lemon juice, scrape the bottom of the pan to detach caramelized bits.
Add vegetable broth and cannellini beans, bring to a boil then reduce to an active simmer. Cook 15 min or until all the vegetables are tender.
Taste and adjust seasoning, adding plenty of fresh pepper.
Add the kale leaves and stir.