Preheat your oven to 350°F (175°C) and line your baking sheets with parchment paper.
In a medium-sized bowl, whisk together the all-purpose flour, baking powder, baking soda, and kosher salt. Set this mixture aside.
In a large mixing bowl, use an electric mixer to cream the unsalted butter, packed light brown sugar, and granulated sugar together until light and fluffy.
Add the eggs, one at a time, mixing well after each addition, then pour in the vanilla extract and mix until fully combined.
Gradually add the dry mixture to the wet ingredients, mixing on low speed until just combined.
Fold in the old-fashioned oats and chocolate chips using a spatula until evenly distributed.
Using a cookie scoop, drop rounded tablespoons of dough onto the prepared baking sheets, spacing them about 2 inches apart.
Bake for 10-12 minutes, or until the edges are golden and the centers look slightly underbaked.
Cool on the baking sheets for about 5 minutes before transferring to a wire rack to cool completely.
