Bring a large pot of water to a rolling boil over high heat and add the spaghetti. Cook according to package instructions, about 8-10 minutes, until al dente.

Wash and chop broccoli into bite-sized florets. In the last 2 minutes of cooking, add the broccoli and frozen edamame to the pot.

In a medium mixing bowl, whisk together peanut butter, soy sauce, chili flakes, sriracha, rice vinegar, and grated ginger. Adjust thickness with warm water if necessary.

Drain the noodles and vegetables. Combine them in the pot or a large saucepan over medium heat and pour the peanut sauce over them, tossing gently to coat.

Serve the noodles in bowls, garnished with green onions, cilantro, crushed peanuts, and extra chili flakes if desired.