Prepare all the ingredients.

Place large nuts like walnuts or almonds in a ziplock bag and crush them into smaller pieces using a rolling pin.

In a pan, combine sugar, corn syrup, and water, and heat without stirring. Use wrist movements to melt the mixture evenly.

Once the syrup is bubbling, add the cereal and nuts, and mix thoroughly using a spatula.

Grease the mold to ensure the bars can be easily removed after setting.

Press the cereal mixture into the mold and flatten the surface evenly.