Heat the oil and butter in a frying pan or wok until the butter has melted.
Add the chicken and cook for 5 minutes, turning once.
Add the garlic and leeks and cook for a further 3 minutes.
Stir in the red pepper, baby corn, sugar, honey, stock, soy sauce, stem ginger, ginger syrup and vinegar. Reduce the heat to a simmer and cook until the chicken is cooked well through, about 20 minutes.
Blend the cornstarch with 4 tablespoons of cold water and stir into the pan. Bring to the boil and cook until the sauce is thickened and clear.