Heat the oil in a large casserole dish with a lid, and brown the chicken - you don't need to fully cook it through at this point.
Add the onions to the pan and cook, stirring frequently, until they start to soften - about 3-4 minutes.
Add the garlic, carrots, squash, thyme and bay and stir well before you add the tomato puree and pour over the stock.
Stir well, then bring to the boil.
Put the lid on the pot then turn the heat to low and allow to simmer for 45 minutes or until the vegetables are tender. Take off the lid and give it a stir once or twice while simmering to make sure nothing sticks to the bottom of the pot.
Add the beans and stir well then leave to simmer with the lid off for a further 15 minutes.
Season with salt and pepper to taste, garnish with some fresh parsley (and some optional chilli flakes if you like a little spice). Serve with your choice of rice, mashed potato or crusty bread to mop up the sauce.
This will keep well in the fridge for 2 days.