Cereal Cookies

Preheat the oven to 350 degrees F (175 degrees C). Line 2 baking sheets with parchment paper.

Combine cornflakes, rice cereal, and oats in a large bowl. Whisk flour and baking soda together in a separate bowl.

Beat butter, oil, and both sugars in a very large bowl until smooth. Add egg and vanilla and beat until smooth. Slowly mix in flour mixture. Stir in cereal mixture by hand.

Drop tablespoonfuls of dough 2 inches apart onto the prepared baking sheets. Flatten balls with the bottom of a glass for even cooking and crispier cookies.

Bake in batches in the preheated oven until edges are golden, 10 to 12 minutes. Cool on the baking sheet for 1 minute before removing to a wire rack to cool completely.