Heat a wok or large non-stick frying pan over high heat until hot. Add the oil and heat until just smoking. Add the garlic and ginger and cook, stirring for 30 seconds. Add the chicken and lemon slices and cook, stirring for 1-2 minutes or until chicken is cooked through. Add the oystersauce and chicken stock and cook for 1-2 minutes or until the sauce has thickened slightly.
Remove from the heat and add basil to serve. Serves 4.