The joy of a yummy sugar cookie, without all the work.
Flour forms the structural backbone of any cut-out or drop cookie, but here it absorbs the moisture of four whole eggs to create a soft, cake-like crumb instead of a crisp edge. Butter at room temperature traps air during the creaming stage, which prevents the dense bars from becoming overly heavy. Whisking the dry components separately ensures the baking soda distributes evenly before hitting the wet mixture, avoiding bitter pockets in the finished pan.
Standard rimmed baking sheets measuring 13 by 18 inches provide the correct surface area for this thick batter, yielding forty uniform portions. Spreading dense dough across a large metal sheet requires an offset spatula dipped in warm water to prevent dragging. Baking at 375 degrees Fahrenheit for 12 to 22 minutes produces a pale golden crust while keeping the interior tender. Cool the entire sheet completely on a wire rack before applying frosting, or residual warmth will melt the butterfat in the topping.
Halving this formulation works well in a standard 9-by-13-inch baking dish without altering the oven temperature. Stand mixers fitted with paddle attachments handle the heavy volume of both dough and buttercream efficiently, though hand mixers require scraping down the bowl frequently to incorporate unmixed pockets of powdered sugar.