Saute mushrooms in oil until mostly browned and the liquid has been released. Add ginger, garlic, and red pepper flakes and saute until no longer fragrant
Add broth, peanut butter, and soy sauce. Simmer for 5 minutes to allow flavors to meld.
Add the ramen noodles to the simmering broth and cook 2-3 minutes or until the noodles are done.
Divide the ramen, broth, and mushrooms between two serving bowls. Top each with desired toppings such as chopped green onion and sliced jalapeno. Serve with lime wedges to squeeze into the ramen if desired.