In the ancient city of Hangzhou, where mist rises from West Lake and the air carries whispers of poets and emperors, there is a humble street snack that has been sizzling on iron griddles for over 800 years. Known as Cong Bao Hui(葱包桧, 葱包烩) – “Scallion Pancake Roll, Scallion-Wrapped Roll” – this crispy, savoury…