- Butter a 10×15 baking pan.
- Melt marshmallows and butter together in a large saucepan over medium heat, stirring until mixture is smooth, about 10 minutes.
- Combine cereal, candy corn, and chocolate chips together in a large bowl. Add marshmallow mixture to cereal mixture and stir together until cereal is well coated. Spread in prepared pan. Cool to room temperature and cut into squares.