Preheat the oven to 350°F (175°C). Grease an 8-inch square baking pan with butter or cooking spray.
In a medium saucepan, combine the butter, brown sugar, and corn syrup. Cook over medium heat, stirring constantly, until the mixture is melted and smooth.
Remove the mixture from the heat and stir in the vanilla extract.
In a large bowl, combine the puffed wheat cereal, chocolate chips, white chocolate chips, and walnuts (if desired). Pour the butter mixture over the cereal and mix until all of the cereal is evenly coated.
Pour the mixture into the prepared baking pan and spread it evenly. Bake for 20-25 minutes, or until golden brown.
Remove from the oven and allow to cool completely before cutting into squares.
Interesting Facts
Puffed wheat is a type of breakfast cereal made from wheat kernels that have been heated and then pressed through a die.
Chocolate chips can be found in a variety of flavors, such as semi-sweet, dark, milk, and white.
Walnuts are a type of tree nut that are high in healthy fats, protein, and fiber.