Step 1

Adjust two oven racks to the lower and upper third of the oven and preheat to 350 degrees F. Line two baking sheets with parchment paper.

Step 2

Add the flour and oats to a food processor and pulse until the oats are finely ground. Transfer to a medium bowl, add the baking soda and 1/2 teaspoon salt and whisk to combine. Whisk together the egg, applesauce and vanilla in a small bowl.

Step 3

Add the butter, granulated sugar and brown sugar to the bowl of a stand mixer fitted with a paddle attachment (or to a large bowl if using a hand mixer). Beat on medium-high until the mixture is light and fluffy, about 4 minutes. Add the applesauce-egg mixture and beat until incorporated, scraping down the sides of the bowl as needed. Reduce the mixer speed to medium-low and add the flour-oats mixture in two batches, mixing until just incorporated. Add the chocolate chips and mix until evenly distributed in the batter.

Step 4

Drop heaping tablespoonfuls of batter onto the prepared baking sheets, about 2 inches apart. All the batter won't fit on the two sheets; cookies will need to be baked in batches. Bake until golden brown, 10 to 12 minutes, rotating the pans halfway through. Let the cookies cool for a few minutes on the baking sheets, then transfer to racks to cool completely. Once the lined baking sheets are cool, repeat with the remaining batter. Store the cookies at room temperature in airtight containers for up to 3 days.