1) Remove the stems of the mushrooms.
2) Chop together shrimps, pork, and scallions until very fine.
3) Blend in 1 tablespoon soy sauce, salt, pepper and flour.
4) Shape the mixture into small balls and stuff the mushrooms.
5) In a large skillet, pour the broth and remaining soy sauce and arrange the mushrooms in it, stuffed side up.
6) Cover and simmer for 20 minutes, or until pork is done.
7) Spear with cocktail picks to serve as an hors d'oeuvre.