Sprinkle meat with mustard and 1/2 teaspoon salt.
Melt the 1/4 cup Lemon-Pepper Butter.
Brown the steaks on both sides in butter; cook over high heat 1 minute more.
Remove to warm platter.
Add mushrooms, Worcestershire, and 3 tablespoons water to drippings.
Bring to boiling.
Return steaks to skillet; heat through.
Add the 2 tablespoons Lemon-Pepper Butter to hot prepared Seasoned Rice Mix.
Serve with steaks.