Line cookie sheet with foil. In 4-quart saucepan, heat sugar, butter, cocoa and milk to boiling over medium-high heat. Boil 2 minutes, stirring frequently; remove from heat. Stir in peanut butter and vanilla until smooth. Stir in granola until well combined.
Quickly drop granola mixture onto cookie sheet by heaping tablespoonfuls. Cool until set, about 30 minutes.