Place rice noodles in enough lukewarm water to cover. Let soak until soft, about 20 minutes. Drain, and set aside.
Meanwhile, in a medium saute pan, heat 2 tablespoons vegetable oil over medium heat. Add curry and turmeric, and cook until fragrant, 1 to 2 minutes. Slowly add chicken stock; stir to combine. Remove from heat, and set aside.
In a wok or large saute pan, heat 2 to 3 tablespoons vegetable oil over medium-high heat. Add onions, garlic, and shallots, and saute until just wilted, 1 to 2 minutes. Add broccoli and cauliflower, season with salt and pepper, and cook for about 1 minute. Add 2 tablespoons water; stir to combine. Add carrots, napa cabbage, and chiles, and cook until the vegetables are al dente, about 2 minutes.
Make a well in the bottom of the wok. Pour 1 tablespoon vegetable oil into center of the well. Add egg. Allow to set slightly, then scramble, and incorporate into the other ingredients.
Add soaked noodles and curry-turmeric mixture to wok. Mix thoroughly to combine. Cook to heat through. Stir in sliced scalions. Season with salt and pepper.
Transfer to serving platter. Garnish with cilantro sprigs. Serve with a spoonful of chile sauce. Serve immediately.