The heat in dan dan noodles comes from the Sichuan red peppercorns in the Sichuan pepper chili oil. They have a numbing spicy characteristic that makes your tongue and lips “zing”. This version of dan dan noodles is spicier than most others due to the addition of pure chili oil and fresh Bird’s Eye red chilies. However, the spiciness in this dish can easily be customized to taste.