1.Place cornflour and mustard powder in a 4.5-litre (18-cup) slow cooker. Gradually whisk in wine and stock until smooth. Add mustard and honey; whisk until smooth.
2.Remove and discard fat and skin from chicken. Place chicken, leek, celery and carrots in cooker. Cook, covered, on low, for 6 hours.
3.Add peas to cooker; cook, covered, 20 minutes. Stir in cream; season to taste. Serve chicken topped with parsley.
Serve with mashed potato. Chicken thigh cutlets usually come with the skin and centre bone intact, although sometimes they can be found without the skin. Poultry shops and most major supermarkets will sell them. We used a chardonnay-style wine. This recipe is not suitable to freeze.