Heat oil on medium heat in large pot.
Add chopped onion.
Cook on medium heat until onion is translucent. About 5 minutes.
Add 2 cups of broth, soy sauce, pepper, salt, red pepper flakes, garlic, and ginger powder.
Bring to low boil and remove from heat.
Add raw shrimp, noodles, cabbage, peanut butter, and remaining broth. (NOTE: if using cooked shrimp add the shrimp after the cabbage has wilted, just to heat it)
Return to heat and heat just until hot (do not let boil), the shrimp is cooked, and the cabbage is wilted.
Serve with a drizzle of chili oil and fresh cilantro.