Cut the tenderloin into 1 cm thick medallions.
Heat most of the oil in a large casserole dish and add the medallions. Season with salt an pepper and cook them for a couple of minutes, turning them over regularly, until they have changed colour completely. Transfer them to a plate.
Meanwhile, chop the onion, celery stick, garlic and carrot.
Ad the rest of the oil to the pan, and sauté the onion and celery for 5 minutes, then add the garlic, red pepper and the herbs.
Stir-fry for 3 minutes, the add the tomato purée, stir for a few seconds, then add the tinned tomatoes.
Season with salt & pepper, and add enough water (using the tin) to cover everything well.
Bring to the boil, then cover and cook for 15 minutes.
Drain the beans and add them to the stew together with the kale. Cook for 5 minutes.
Add the pork medallions and cook for another 5 minutes or so, until the pork just cooked through. Don’t overcook the pork if you don’t want it become rubbery!