Using a sharp knife,held almost parallel to cutting surface,cut partially frozen flank steak into very thin slices.In 12" skillet over medium high heat,heat oil;add beef;cook 2 to 3 minutes,stirring frequently until browned.Using slotted spoon,remove meat to plate; keep warm.To drippings in skillet,add red bell pepper,onion,ginger, garlic and crushed red pepper.Cook about 4 minutes,stirring constantly until vegetables are crisp-tender.add pea pods,escarole,soy sauce and brown sugar.Cook about 1 minute,stirring constantly until pea pods are heated through and escarole is wilted.Stir beef into vegetables. Makes 4 servings.