Whisk the flour, sugar, baking soda, and kosher salt together. In a 1-quart jar, layer the flour mixture (divided into thirds and layered between the other ingredients), sprinkles, brown sugar, M&M's, chocolate chips, and crisp rice cereal. Prep time: 10 minutes. Total time: 40 minutes. Makes 18 cookies. Beat 1 stick salted butter (softened) in a large bowl with a mixer until light, 1 minute. Add 1 egg and beat until smooth, 1 minute. Add 1 teaspoon vanilla; beat until combined. Add the Loaded Holiday Cookie Mix; mix until the dough comes together. Scoop 18 spoonfuls of the dough onto parchment-lined baking sheets. Chill 15 minutes. Bake at 350 ̊ until golden brown, 12 to 14 minutes.