Averie Cooks

-1 To the bowl of a stand mixer fitted with the paddle attachment, combine the butter, sugar, egg, extract, and beat on medium-high speed until well-creamed, light and fluffy, about 5 minutes (or use a hand mixer and beat for at least 7 minutes). Do not shortcut the creaming process; make sure dough is very light in color and fluff, stop to scrape down the sides of the mixer as necessary.
-1 Stop, scrape down the sides of the bowl, and add the flour, cornstarch, baking soda, optional salt, and mix until just combined, about 1 minute.
-1 Add the sprinkles and beat momentarily to incorporate, less than 1 minute, or fold in by hand.
-1 Using a medium 2-inch cookie scoop, form heaping two tablespoon mounds (I made 15). Place mounds on a large plate, flatten mounds slightly with your palm, cover with plasticwrap, and refrigerate for at least 2 hours, or up to 5 days, before baking. Do not bake with warm dough because cookies will spread and bake thinner and flatter.
-1 Preheat oven to 350F, line two baking sheets with Silpats, or spray with cooking spray. Place mounds on baking sheets, spaced at least 2 inches apart (I bake 8 cookies per sheet). Bake for 8 minutes, or until edges have set and tops are just beginning to set, even if undercooked, pale, and glossy in the center. These cookies should not turn golden or brown at all and should stay white. Do not bake longer than 9 minutes for soft cookies because they firm up as they cool (The cookies shown in the photos were baked with dough that had been chilled overnight, allowed to come to room temp for 15 minutes, and were baked for 8 minutes, with trays rotated at the 4-minute mark). Allow cookies to cool on the baking sheet for about 5 minutes before removing and transferring to a rack to finish cooling.
-1 Store cookies airtight at room temperature for up to 1 week, or in the freezer for up to 3 months. Alternatively, unbaked cookie dough can be stored airtight in the refrigerator for up to 5 days, or in the freezer for up to 4 months, so consider baking only as many cookies as desired and save the remaining dough to be baked in the future when desired.