1, Preheat the oven to 250°F. Bring a medium pot of water to a boil over high heat. When the water is boiling, add the broccoli and cook until just tender, about 5 minutes. Drain, rinse with cold water, and set aside.
2, In a wok or heavy bottomed pot, heat 2 inches of oil to 350°F. Divide the noodles into 6 portions, and form each portion into a loose ball about 5 inches in diameter. When the oil is hot, place one ball of noodles on a spider or two slotted spoons and gently lower into the hot oil. The noodles will spread into a disc about 8 inches wide.
3, Cook the noodles for 1 minute or until golden brown. With the spider or slotted spoons, remove the noodles from the oil and drain on paper towels. Repeat with each portion of noodles, allowing oil to return to 350°F between batches. When all of the noodles have been fried, put on a sheet pan and place in the oven to keep warm. If you fried the noodles in your wok, let the oil cool slightly, then carefully pour out into a heatproof bowl. Save for future frying or discard once it has cooled.
4, In a small bowl, mix cornstarch with ¾ cup cold water, stirring until smooth. Set aside. Heat a wok over high heat; the metal will have a matte appearance and a drop or two of water flicked onto its surface should evaporate on contact. Add 2 tablespoons of the oil and the onions and cook, tossing frequently, until they begin to soften, about 3 minutes. Add half of the broccoli, carrots, and shiitake mushrooms, toss, and cook 1 to 2 minutes more. Add half of the shrimp, squid, and scallops and cook 1 minute more, tossing frequently. Deglaze the wok with half of the rice wine and cook 30 seconds more. Add half of the chicken stock, sugar, fish sauce, stir-fry sauce, sesame oil, and cornstarch slurry. Bring to a boil, then reduce the heat so the liquid is simmering and simmer 2 minutes, until the sauce thickens slightly.
5, Place 3 of the fried noodle disks on individual plates and divide the seafood mixture and sauce evenly over the top of the noodles.
6, Wipe the wok clean and repeat steps 4 and 5 using the remaining ingredients. Serve immediately.