• Add the flour to a quart-sized mason jar, making sure to spoon and level when measuring.
  2 cups bread flour
• Add in the powdered milk, cornstarch, salt, and baking soda.
  1 tablespoon powdered milk, ½ tablespoon cornstarch, ¾ teaspoons salt, ½ teaspoon baking soda
• Layer on the light brown sugar, pressing and packing it down and spreading it out to the sides of the jar with a spoon.
  ¾ cups light brown sugar
• Add the granulated sugar and make sure to level out to the edges of the jar.
  ½ cup granulated sugar
• Add the chocolate chips, then the M&Ms, and top with the sprinkles.
  ½ cup semi-sweet chocolate chips, ½ cup M&Ms, 2 tablespoons holiday sprinkles
• Seal and label. Best to use within 1 month of prepping.

When Ready To Prepare

• Preheat the oven to 375°F and line a baking sheet with parchment paper and set aside.
• Add the contents of the jar along with the butter, egg, and vanilla to a large bowl or stand mixer fitted with a paddle attachment and mix until combined. It may take a few minutes to come together and will look sandy at first, but it will ultimately turn into a typical cookie dough texture.
  ¾ cup unsalted butter, 1 large eggs, 1½ teaspoons vanilla extract
• Use a large cookie scoop to portion out and drop the dough on the prepared baking sheet. Top with additional chocolate chips, M&Ms, and sprinkles if you have any on hand. The cookies in the photos are made with a medium scoop (see notes), but my family prefers the texture of the large scoop cookies.
• Bake for 10 to 13 minutes until the edges are just golden brown.
• Allow the cookies to cool on the pan for several minutes before transferring them to a wire rack. They can also cool completely on the pan if you use a second baking sheet to bake off the rest of the cookies.