8 ounces (about) rice noodles (vermicelli or sticks, as you like)
8 ounces bean sprouts
1/2 cup peanut butter
1 teaspoon sugar
3 tablespoons fish sauce, or to taste
2 small hot red chiles (like Thai bird or Fresno), seeded if you like and chopped
1 tablespoon fresh lime juice, or to taste
1/2 cup chopped scallions
1/4 cup chopped roasted peanuts
Bring a large pot of water to a boil and salt it. Put the noodles in a large bowl. When the water boils, add enough water to the bowl to cover, stir, then let the noodles soak until they are soft and pliable. Start checking after 3 minutes; thicker noodles could take up to 15.
When the noodles are nearly tender, add the sprouts to soak for a minute or reserve 1/2 cup of the soaking liquid, then transfer everything to a colander, run under cold water for 1 minute, and shake off any excess water.
Meanwhile, bring the remaining water back to a boil, carefully add the eggs, cover, and turn off the heat. Steep the eggs for 9 minutes, then drain and run under cold water until cool.
Whisk together the peanut butter, sugar, fish sauce, 1 teaspoon of the chiles, and the lime juice in a small bowl. Add 1/4 cup of the reserved liquid and continue to whisk. The dressing should easily coat the back of a spoon. If it’s too thick, whisk in more hot water 1 tablespoon at a time. Taste and adjust the seasoning, adding more lime juice, chiles, and salt if you’d like.
Combine the noodles and sprouts with half the dressing in a large bowl and toss gently with 2 forks.
Peel the eggs and halve lengthwise.
Garnish the noodles with the eggs, scallions, and peanuts and serve at room temperature, passing the lime wedges and the remaining dressing and chiles at the table.