Bring a few inches of oil in a pot or wok to 350f or until a piece of noodle fluffs up immediately. Cut the noodles into short, manageable lengths with kitchen shears. Cook a small bundle of noodles at a time - they take only a matter of seconds to puff up, so if you cook them a few at a time, they won't overcook.
As each bundle is cooked, remove and drain on paper towels. You may choose to keep them warm in the oven at its lowest temperature, but I don’t bother.
Heat 1 tablespoon of the oil in a second wok or large skillet. Add the shallots and stir-fry for 2-3 minutes.
In the meantime, boil a pot of water for the fresh noodles.
Add the garlic, jalapeno (from the first set of ingredients above), bean sprouts, chicken and pork and toss for another 3 minutes or until the ground meat is cooked through.
Toss the fresh noodles into the water for 10 seconds. That's right, SECONDS. Remove, drain and rinse quickly in a colander with cool water.
Reduce the heat of the skillet mixture and season with sugar, fish sauce and vinegar and mix well. Turn off the heat and add the lime juice and soy sauce, if using. Add the drained fresh noodles and mix gently.
Put 2/3 of the crispy noodles onto a large heated serving dish. Add the cooked mixture, then the chopped jalapeno, cilantro and scallions and top with the remainder of the crispy noodles and serve. Alternately you can portion the ingredients out onto 4 dishes. Let diners scatter more cilantro, scallions, or finely diced jalapenos onto their serving as they wish.