Another great recipe from King Arthur Flour.

INGREDIENTS

1 cup unsalted butter, at room temperature
1 cup light brown sugar, packed
1/2 cup granulated sugar
1 large egg, at room temperature
1 large egg yolk, at room temperature
1 tablespoon vanilla extract
2 cups flour
1 cup old-fashioned oats
1 teaspoon baking powder
1 teaspoon baking soda
1 teaspoon kosher salt
6 oz semi-sweet chocolate, chopped

DIRECTIONS

Preheat the oven to 325°F. Line several cookie sheets with parchment paper, or lightly grease with non-stick vegetable oil spray.

Beat together the butter and sugars until smooth. Beat in the egg, egg yolk, and vanilla.

Whisk together the flour, oats, baking powder, baking soda, and salt, and add to the butter mixture in the bowl. Mix until everything is thoroughly incorporated. Scrape the bottom and sides of the bowl, and mix briefly. Stir in the chocolate chips.

Scoop the dough onto the prepared baking sheets, leaving about 1 1/2″ to 2″ between cookies.

Bake the cookies for 12-18 minutes, (depending on the size) until they’re a light golden brown, with slightly darker edges. 

Remove the cookies from the oven, and as soon as they’re set enough to handle, transfer them to racks to cool.