Spray a large mixing bowl and an 8x8" pan with cooking spray.
Add cereal, almonds, and raisins to the bowl.
Mix peanut butter and syrup together in a small saucepan; heat over medium until bubbly. Remove from heat and stir in vanilla; pour over cereal mixture. Stir until well combined.
Transfer mixture to the prepared dish and press down with a spatula to evenly distribute.