Make-ahead tip: The sauce keeps in an airtight jar in the fridge for up to 5 days. Cooked, dressed noodles keep for up to 3 days — add a splash of sesame oil and toss to refresh before serving. For a complete protein meal, add shredded rotisserie chicken, sliced tofu, or a handful of shelled edamame. For gluten-free: use 100% buckwheat soba noodles and tamari instead of soy sauce. For nut-free: substitute tahini or sunflower seed butter for the peanut butter.