3eggs, at room temperature, cracked into a small bowl
1/8teaspoonfine sea salt
3cupsall-purpose flour, plus an additional 1/4 cup for shaping the dough
4 to 5cupsfrosted flakes cereal of your choice
In a stand mixer, fitted with the paddle attachment, whip the butter until soft and fluffy, about 2 minutes. Add the sugar 1/4 cup at a time, beating well after each addition.
Scrape down the sides of the bowl and the beaters. Add the eggs and continue beating until well mixed, another minute. Beat in the vanilla and salt. Add the flour 1/4 cup at a time, beating for a few seconds after each addition, and continue to beat until the flour is incorporated. The batter should be very smooth, homogenous and soft. Remove the bowl from the mixer.
Cover 2 large baking sheets with parchment paper. Preheat the oven to 325 degrees Fahrenheit and position the oven racks in the middle and bottom thirds.
Place 2 cups of frosted flakes on a large dinner plate or baking sheet and using your hands, squeeze and crumble the flakes to make them smaller, taking care not to grind them up completely. Place 1/4 cup flour on another plate and set it next to the plate with the frosted flakes, and have the parchment-covered baking sheets nearby.
Dust your hands with the flour on the plate and scoop up about 1/4 cup of dough. Roll it into a ball and flatten the ball slightly in your hands, then put it into the crumbled frosted flakes to “bread” the cookie. Gently press the ball of dough into the flakes as you add about a teaspoon of crumbs to the top, then press into a ¼-inch thick, 3- to 4-inch round. Transfer to the baking sheet and repeat with rest of the dough.
Bake 20 to 25 minutes, rotating the pans from top to bottom and front to back halfway through, until the cookies are light golden brown around the edges. Remove from the oven and allow to cool. Store in a tin or a jar.