Preheat the oven to 220°C.
Heat half the oil and butter in an ovenproof pan and fry chicken until golden.
Add one halved shallot, lemon, half the herbs, and garlic bulb to the chicken pan.
Roast in the oven for 15 minutes until the chicken is cooked through.
Finely chop the remaining shallot and reserved garlic cloves.
Fry chorizo in the remaining oil for 5 minutes until crisp.
Add tomatoes, chopped garlic, and shallot, then stir in beans and remaining herbs.
Pour in the chicken stock and simmer for 5 minutes until liquid reduces slightly.
Stir in the remaining butter and parsley, then season with pepper.
Serve beans topped with chicken, roasted shallot, lemon, and garlic.