Pulse the old-fashioned oats in a food processor about 10 times, then set aside.

Whisk together the all-purpose flour, oat mixture, malted milk powder, baking soda, and salt in a mixing bowl.

In a stand mixer, cream the butter and sugars until light and fluffy, about 2-3 minutes.

Beat in the egg and vanilla extract until smooth.

Gradually add the dry mixture to the wet ingredients while mixing on low speed.

Cover the dough and refrigerate for at least 2 hours.

Preheat the oven to 350°F (175°C) and prepare baking sheets.

Using a cookie scoop, portion out the dough onto the sheets, spacing about 2 inches apart.

Bake for 9-11 minutes until edges are lightly browned.

Cool cookies on the baking sheets for 5 minutes then transfer to a wire rack.