Heat the oil in a wok or large skillet over high heat until hot but not smoking. Add the garlic and sauté, stirring, about 20 seconds, just until fragrant. Add the shrimp and cook, stirring, about 2 minutes, until pink and not quite cooked through. Stir in the noodles until coated with the oil.
Add the sauce to the noodles and cook, stirring occasionally, 5 to 7 minutes, or until the liquid is absorbed; add water if necessary to soften the noodles. Stir in the tofu.
If using the eggs, create a well in the center of the wok by pulling the noodles to the side. Add the eggs and cook, stirring, until firm. Stir in the scallions, peanuts and bean sprouts; blend well and heat through. Transfer the noodles to a serving platter and garnish with the red pepper, bean sprouts, peanuts and lime.
For a healthier version: Reduce the fish sauce and brown sugar to 2 tablespoons each. Cut the vegetable oil to 1 tablespoon, and use only baked tofu. If using eggs, substitute one egg white for one of the eggs. Use dry roasted peanuts, and reduce to 1/4 cup.
Recommended ingredients: Fish sauce and tofu are available at most supermarkets, specialty stores and health food stores.
(Healthier version without eggs) 463 calories, 12 grams fat, 2 grams saturated fat, 991 mg sodium, 58 grams carbohydrate, 31 grams protein