Slow-cooker honey mustard chicken

Ingredients

• 2 tablespoon cornflour (cornstarch)
• 2 teaspoon dry mustard powder
• 1/2 cup (125ml) dry white wine
• 1 cup (250ml) chicken stock
• 1/4 cup (70g) wholegrain mustard
• 2 tablespoon honey
• 8 chicken thigh cutlets (1.6kg)
• 1 medium leek (350g), trimmed, sliced thickly
• 2 celery stalks (300g), rimmed, sliced thickly
• 400 gram baby carrots, peeled
• 1 cup (120g) frozen peas
• 1/3 cup (80ml) pouring cream
• 1/4 cup coarsely chopped fresh flat-leaf parsley