Line an 8-inch square baking pan with aluminum foil, extending foil over edges of pan. Blend peanut butter, almond extract and butter in large bowl; stir in powdered sugar.
Add cereal; mix well, crushing cereal slightly.
Press peanut butter mixture evenly into prepared pan with rubber spatula.
Sprinkle top with chopped peanuts; press gently. Chill. To serve, remove from pan by lifting foil; remove foil.