Step 1

Preheat the oven to Line a light-colored baking sheet with a silicone mat.

Step 2

In a medium bowl, beat the butter with an electric mixer on medium speed until fluffy, about 20 seconds.

Step 3

Add the sugars, and beat for about 30 seconds. The mixture will turn a pale color and be fluffy.

Step 4

Next, add the egg yolk and vanilla and beat until just combined.

Step 5

Whisk together the flour, oats, salt, baking soda and baking powder in a separate bowl.

Step 6

Sprinkle the flour on top of the butter mixture, and beat just until combined.

Step 7

Stir in the chocolate chips.

Step 8

Scoop the dough into 6 large dough balls, and space them evenly on the baking sheet.

Step 9

Bake for 10-11 minutes, removing the cookies from the oven when the edges just start to turn golden brown.

Step 10

Let the cookies rest on the baking sheet for 1 minute before moving them to a wire rack to cool.