6 cups low-sodium vegetable stock
1 tablespoon kosher salt
12 ounces Chinese wheat noodles or other flat-style noodles
1/2 cup creamy peanut butter
2 tablespoons soy sauce
2 tablespoons rice vinegar
1 tablespoon sesame oil
Red pepper flakes, to taste (optional)
1-2 bell peppers, cut into thin slices, divided (See Recipe Note)
1/2 cup roughly chopped peanuts, divided
Cilantro leaves and lime wedges for garnish
In a large pot, bring the stock and salt to a boil. Add the noodles and cook until al dente, 3 to 4 minutes. Reserve two cups of the cooking broth before straining. Run the noodles under cold water and shake to remove excess liquid before returning them to the empty pot.
In another bowl, combine the peanut butter, soy sauce, vinegar, sesame oil, and 1/4 cup hot cooking broth and whisk vigorously until mixed. (It will be quite thick.) Toss the peanut sauce with the noodles until coated. Stir in additional hot cooking broth — a few splashes at a time — until the dish is smooth and creamy. (You will probably not need all of the reserved broth.) Taste and season with red pepper, additional soy sauce, and rice vinegar if desired.
Fold in 2/3 of the bell peppers and 1/4 cup peanuts. Transfer noodles to serving dish and garnish with remaining peppers and peanuts. Garnish with cilantro leaves and lime wedges. This can be served warm, cold, or at room temperature.