Rinse the cannellini beans over a sieve with running water, set aside.
Peel and dice an onion and bell pepper into larger cubes, set aside. Peel a carrot and cut into slices, and cube potatoes into 1/2 inch cubes.
Heat oil on a saucepan, once hot, add onion and bell pepper, frying for 3-5 minutes on a medium heat, meanwhile heat water in a kettle.
Squeeze tomato paste followed by seasonings, and a splash of water, stir to combine into a diluted paste, bring to a boil. Follow up with drained beans and tomato blocks, stir and turn the heat down to medium.
Dissolve stock in a mug of hot water from the kettle, add to the saucepan. Bring to a boil, then turn down to a low-medium heat, cover and simmer for a further 20-25 minutes to thicken.
Once beans are cooked through, add a crack of black pepper and some salt to taste. Serve and enjoy with your favourite sides.