How to Make It
Whisk together the flour, baking powder, baking soda, and salt in a bowl.
Beat the butter and sugars in a bowl with an electric mixer on medium-high until light and fluffy, 2 to 3 minutes. Beat in the eggs, one at a time, then the vanilla, scraping down the sides of the bowl as necessary. Reduce mixer speed to low and gradually add the flour mixture, mixing until just combined. Fold in the chocolate chips, pecans, cereal, and pretzels. Chill for 1 hour and up to 2 days.
Heat oven to 325° F. Line 2 baking sheets with parchment.
Drop mounds of dough (about 1/4 cup each) 4 inches apart on the baking sheets. Bake, in batches, rotating the sheets halfway though, until golden brown around the edges, 22 to 24 minutes. Let cool slightly on the baking sheets, then transfer to a wire rack to cool completely.
Tip: Forgot to bring the butter to room temperature? Simply start beating the butter and sugars on a low speed until soft, then increase the speed to medium-high before adding the remaining ingredients.