Place a large dutch oven or heavy-lidded pan on a medium heat. Season the chicken thighs with salt and pepper.
Drizzle about 2 tbsp olive oil into the pan.
Add the chicken pieces and cook for about 5 minutes on a medium/high heat or until golden brown.
Remove the chicken from the pan and keep aside.
In the same pot, add 1 more tablespoon of olive oil and add the onions and herbs to the pan and cook for at least 5 minutes.
Add in garlic, fry for a further 30 seconds and stir in the tomato puree.
Add in the flour and cook for 2 minutes.
At this point, you can add the canned tomatoes, stock and season with salt and black pepper.
Simmer the sauce for about 5 minutes.
Add the chicken pieces, celery and beans.
Bring to the boil then turn down to a simmer. Place the lid on and cook on the stove, under low heat for around 1 hour 15 mins.
Alternatively, you can cook this in the oven.
Serve with rice, bread or mashed potatoes.