Sauté the aromatics: Heat the olive oil in a large frying pan over medium heat. Add the diced onion and cook for 4-5 minutes until it turns translucent and smells sweet and savoury. Stir in the minced garlic, carrots, and celery, and cook for another 3 minutes until the vegetables soften slightly and you hear a gentle sizzle.

Add the spices: Sprinkle in the dried rosemary, thyme, smoked paprika, black pepper, and salt. Stir everything together for about 30 seconds until the spices become fragrant and the kitchen fills with a warm, earthy aroma.

Transfer to the slow cooker: Scrape the sautéed vegetable mixture into your slow cooker. Add the chopped tomatoes and the chicken or vegetable stock. Stir well, and you'll see a rich, reddish-brown liquid forming.

Add the beans: Tip in the drained and rinsed cannellini beans. Give everything a good stir so the beans are evenly distributed throughout the broth. The beans will look pale and plump against the deep colour of the stock.

Cook the soup: Cover the slow cooker and cook on high for 4 hours or on low for 7 hours. After about 2 hours on high, you'll notice the broth deepening in colour and the vegetables becoming tender when you press them against the side of the pot.

Add the kale: About 20 minutes before serving, stir in the chopped kale. Push it down into the hot liquid — you'll see the bright green leaves wilting almost immediately. Cover and let it cook for 15-20 minutes until the kale is tender but still has a slight bite to it.

Finish with lemon: Squeeze in the juice of one lemon and stir. The acidity brightens the entire soup, cutting through the richness of the beans. Taste and adjust salt and pepper if needed.

Serve and garnish: Ladle the soup into bowls while it's steaming hot. The broth should be thick and velvety, with chunks of tender vegetables and creamy beans visible throughout. Sprinkle with fresh parsley and a generous grating of Parmesan if you like.