4 ounces mushrooms, such as shiitake and cremini, stems removed and halved
2 garlic cloves, thinly sliced
2 cups julienned carrots (from about 3/4 pound carrots)
4 scallions, cut into 1-inch pieces, plus thinly sliced scallions, for garnish
1/3 cup frozen sweet peas
2 large eggs, beaten
1 cup bean sprouts
1/4 cup ground roasted peanuts
1 lime, cut into 8 wedges, for serving
Put the noodles in a large bowl and cover with very hot water. Let soak until just pliable, about 15 minutes (or according to package directions). Drain the noodles in a colander, shaking off excess water.
Meanwhile, in a small bowl, whisk the fish sauce with the oyster sauce, sugar and Sriracha.
In a large nonstick wok or skillet, heat the oil until shimmering. Add the shallots, and mushrooms and cook over high heat, stirring occasionally, until lightly browned, about 5 minutes. Add the garlic and carrots and stir-fry until soft, 2 minutes. Add the noodles, the 4 scallions and the peas and stir-fry until heated through, about 2 minutes.
Scrape the noodles to one side of the pan and add the eggs. Cook, stirring occasionally, until nearly set, about 1 minute. Toss everything together. Add the sauce and stir-fry until the noodles are evenly coated and the sauce has thickened slightly, 2 to 3 minutes. Transfer the pad Thai to a platter. Garnish with the bean sprouts, peanuts and thinly sliced scallions and serve with the lime wedges.