Bring a large pot of water to boil. Cook linguine as package directs. Stir together broth and soy sauce in a measuring cup.
Heat a large skillet over medium-high heat. Add ground pork and red pepper flakes. Cook 5 minutes, breaking up, until browned and no longer pink. Add scallions, carrot, garlic and ginger; cook 3 minutes.
Stir broth mixture and peanut butter into pork. Cook until peanut butter is melted and blended.
Reserve 1 cup pasta water. Drain linguine, add to skillet and toss to evenly coat with sauce. (Stir in some pasta water if needed to keep mixture creamy). Sprinkle with cilantro.