In large skillet, combine first 3 ingredients. Cook over medium heat until browned, stirring to crumble beef. In a saucepan, slowly heat spices in butter. Drain beef. Wipe skillet dry with a paper towel. Return beef mixture to skillet; add chopped spinach, spices and salt; stir well. Cover and cook over medium heat 5 minutes or just until spinach is wilted; remove from heat. Line each pita half with whole spinach leaves. Spoon 1/2 cup beef mixture into each pita half. Mix sour cream or yogurt with curry powder. Top each pita half with 1 tablespoon sour cream or yogurt.
