Step 1
Prepare the noodles: Place dried noodles in a large bowl and cover with hot tap water. Let soak while you prepare the remaining ingredients, allowing the water to cool, and stirring and separating the noodles occasionally with your hands. (This will take 30 to 40 minutes, depending on the brand.) When ready, noodles will be white, limp and almost soft to the bite. (They will cook a little more later on.) Pour off all the water, fluff noodles with your hands, and set aside.
Step 2
Meanwhile, make the sauce: In a bowl, combine the oyster sauce, soy sauce, fish sauce, vinegar and black soy sauce.
Step 3
Make the noodles: Remove the stems and seeds from the chiles. Using the flat side of a wide, heavy knife, smash the garlic and chiles. If you have a mortar and pestle, crush the peeled garlic and seeded chiles into a rough paste. If not, use a small food processor to mince together, or just use the knife to mince the garlic and leave the smashed chiles whole.
Step 4
Place the remaining ingredients in bowls and line them up in the order they’ll be added to the pan: protein, greens (if using), noodles, sauce and basil. When ready to cook, put 1 cup of hot tap water near the stove.
Step 5
Heat the oil in a 14-inch wok, a heavy 12-inch skillet or a large Dutch oven over medium until shimmering. (If using a smaller pan, cook in 2 batches.) Add garlic mixture and stir-fry over medium heat just until sizzling and fragrant, stirring with a wok turner, spatula or tongs, 30 to 45 seconds.
Step 6
Add the protein, raise the heat to high and stir-fry for 2 minutes. If using, add gai lan. Keep cooking until protein is just cooked through and greens are wilted, 1 to 2 minutes longer.
Step 7
Add noodles, spreading them around the pan, tossing and separating them. When noodles are sizzling, add 3 tablespoons sauce and stir-fry, tossing to coat and cook through.
Step 8
Taste noodles for doneness and seasoning. If needed, add more pad kee mao sauce a little at a time until the dish is spicy and savory and not too sweet. Add hot water, 1 tablespoon at a time, if noodles are not quite soft.
Step 9
When the noodles have absorbed all the sauce and the flavors are balanced, add the basil leaves and toss to combine. Serve immediately.