Bash the chicken out slightly so every piece is of equal thickness all over. I set it between 2 pieces of clingfilm and hit it gently with a rolling pin
Season with salt and pepper then dredge in the flour until evenly coated
Heat half of the oil in a frying pan over a medium heat and brown the chicken pieces on each side. Don't cook them right through
Remove and set aside on a warm plate
Heat the rest of the oil and add the onion, mushrooms and garlic to the pan
Cook until they start to brown then add the chicken back in with the stock and the rosemary. Season again with salt & pepper
Cover and turn the heat down to let simmer gently for 5 - 10 minutes until the chicken is cooked through and the sauce has reduced
Discard the rosemary sprigs and serve with seasonal vegetables
