In large buttered bowl, combine first 4 ingredients; set aside. In medium saucepan combine sugar, corn syrup and water; bring to a boil. Cook, covered 3 minutes. Uncover and cook, without stirring, until mixture reaches a hard, ball stage, 4-5 minutes. Add butter and vanilla; cook, stirring 1 minute. Pour over popcorn mixture; toss quickly to coat. Turn mixture out onto greased baking sheet and spread using buttered hands. Cool and break into pieces.