Food Processor Method In a food processor, pulse together the brown sugar, granulated sugar, oats, and salt until well combined. Add the flour, butter, and vanilla and pulse until the mixture is coarse and crumbly. Empty the mixture into a small bowl and, with your fingertips, lightly pinch it together to form little clumps.

Electric Mixer Method In the bowl of a stand mixer fitted with the flat beater, on medium speed, mix the butter, brown sugar, granulated sugar, and vanilla until smooth and creamy.

In a medium bowl, whisk together the flour, oats, and salt. Add this mixture to the butter mixture and mix on low speed just until incorporated. Remove the bowl from the stand and, with your fingers, lightly pinch together the mixture to form little clumps.