Confetti Cookies

Directions

1. 1
   For the Birthday Cake Crumb:
2. 2
   Heat oven to 300 F.
3. 3
   Combine the sugars, flour, baking powder, salt and sprinkles in the bowl of a stand mixer fitted with a paddle attachment and mix on low until well-combined.
4. 4
   Add the oil and vanilla and mix to combine. The wet ingredients act as a glue to allow the dry ingredients to form clusters. Continue to mix until that happens.
5. 5
   Spread the clusters on a parchment-lined sheet pan and bake for 20 minutes, breaking them up occasionally, as needed. Mine actually only took 18 minutes or so. Take them out of the oven before they harden; they should remain slightly moist to the touch. They will harden as they cool.
6. 6
   Let the crumbs cool completely before using in this recipe. The cookie recipe only calls for half of the cake crumbs, which is a heaping 1-cup full. Store extras in an airtight container for up to 1 week at room temperature or up to 1 month in the refrigerator or freezer.
7. 7
   For the Confetti Cookies:
8. 8
   Combine the butter, sugar and glucose in the bowl of a stand mixer fitted with a paddle attachment and cream on medium-high speed for 2-3 minutes. Scrape down the sides of the bowl and add the eggs and vanilla and mix for 7-8 minutes. At the end of 7-8 minutes the mixture should be very pale yellow and doubled in size. It should be very shiny, homogenous, fluffy and resemble a cloud.
9. 9
   Reduce the mixer speed to low and add in the flour, milk powder, cream of tartar, baking soda, salt and sprinkles. Mix just until the dough comes together, not longer than 1 minute. Note: don't walk away during this step, just to make sure that you don't over mix the dough. Scrape down the sides of the bowl.
10. 10
    With the mixer on low speed, add 1 cup of birthday cake crumbs and mix in for about 30 seconds, just until incorporated.
11. 11
    Scoop the dough onto a parchment- or Silpat-lined sheet pan using a 2 3/4 ounce ice cream scoop (mine is a #16), or use a 1/3 cup measuring cup. Flatten the cookies slightly and wrap the pan in plastic wrap. Refrigerate for at least one hour. I refrigerated mine overnight. Do not bake at room temperature or they won't bake correctly.
12. 12
    When ready to bake, heat the oven to 350 F.
13. 13
    Arrange the chilled dough a minimum of 4 inches apart on a parchment- or Silpat-lined baking sheet. Bake for 18 minutes. The cookies will puff, crackle and spread. After 18 minutes they should be very lightly browned on the edges. The centers will just slightly show a change in color. Leave the cookies in the oven for another minute or so if they seem doughy or the colors aren't quite right. Mine were perfect at exactly 18 minutes; I rotated the pans once, halfway through cooking.
14. 14
    Cool the cookies completely on the sheet pans before transferring to store. At room temperature the cookies will keep for 5 days. They'll keep for 1 month in the freezer.
15. 15
    Recipe adapted from Christina Tosi via Momofuku Milk Bar Cookbook.