Preheat your oven to 350°F (175°C). This ensures that your cookies bake evenly and achieve that perfect crispiness.
Line a baking sheet with parchment paper. This will help your cookies bake evenly and prevent them from sticking.
In a medium bowl, whisk together 1 cup of all-purpose flour, 1/2 teaspoon of baking powder, 1/2 teaspoon of baking soda, and 1/4 teaspoon of salt. Set aside.
In a large mixing bowl, cream together 1/2 cup of unsalted butter, 1/2 cup of granulated sugar, and 1/2 cup of light brown sugar until the mixture is light and fluffy.
Beat in 1 large egg and 1 teaspoon of vanilla extract to the butter and sugar mixture until well combined.
Gradually add the dry ingredients to the wet ingredients, mixing just until combined. Be careful not to overmix.
Fold in 1 cup of old-fashioned oats, 1 1/2 cups of Rice Krispies cereal, 1 cup of chocolate chips, and 1 cup of chopped Butterfinger candy bars until evenly distributed throughout the dough.
Using a cookie scoop or tablespoon, drop dough onto the prepared baking sheet, spacing them about 2 inches apart. Bake in the preheated oven for 10-12 minutes, or until the edges are golden brown.
Allow the cookies to cool on the baking sheet for a few minutes before transferring them to a wire rack to cool completely. Enjoy your crispy, buttery creations!