Optional: Cucumber raita and chopped fresh cilantro
Preheat oven to 400°. Flatten bread slices with a rolling pin; brush tops with butter. Set aside.
In a large skillet, cook beef and celery over medium heat until beef is no longer pink and celery is tender, 8-10 minutes, breaking beef into crumbles; drain. Stir in bread crumbs, curry powder and garlic salt.
Spoon beef mixture evenly among bread slices. Roll up bread slices; secure with toothpicks. Place on a greased baking sheet. Bake until golden brown, 12-15 minutes. When cool enough to handle, discard toothpicks and cut each roll-up crosswise into 3 slices. If desired, serve warm with cucumber raita and chopped fresh cilantro.