Divide ramen noodles evenly in center of each of the 4 pieces of aluminum foil. Stack the following ingredients on top of noodles, in this order: mushrooms, shrimp, onions, scallions, red pepper flakes, and salt. Pull sides and corners of pouch up to form a small basket shape leaving an opening at the top to pour in liquid.
In small bowl, combine vegetable broth, mirin, soy sauce, and sesame oil. Distribute liquid evenly among packs. Press foil together, leaving a small opening to allow steam to escape. Place on cookie sheet and bake in oven for 15 minutes. Serve immediately.