1.4 kg (3 lb) oven-ready chicken, skinned and boned
700 g (1 1/2 lb) floury potatoes, peeled and sliced into thick matchsticks
225 g (8 oz) leeks, trimmed and sliced
439 g (15 1/2 oz) can butter beans, drained
salt and freshly ground pepper
450 ml (3/4 pint) chicken stock
10 ml (2 tsp) dijon mustard
15 ml (1 tbsp) tomato puree
25 g (1 oz) butter chopped parsley, to garnish