Preheat oven to 350°F and prep your 9-inch springform pan (or pie dish) by spraying with cooking spray
In a large bowl, using either a hand-held mixer or stand mixer, beat the butter for about a minute on medium speed.
Once butter is smooth and creamy add in the brown sugar. Beat on medium speed for about 1 minute. Scraping down the bowl as needed. The goal is to not see any visible butter.
Add in egg, egg yolk, and vanilla. Mix on medium-high speed until incorporated.
Add in chocolate chips. Mix until fully dispersed.
In a separate bowl, combine dry ingredients.
With the mixer on low, gradually add the dry ingredients to the wet ingredients.
Transfer dough to prepared pan. Using clean hands or a spatula, press the dough into the pan making sure it is as even as possible.
Cover the pan with tin foil and bake for 15 minutes.
Remove the foil and bake for an additional 10 minutes, or until the cake is done (I like to test by sticking a toothpick into the middle of the cake, if it comes out clean then the cake is done).
Once done, remove from the oven and set the pan on a cooling rack. After the cake has fully cooled, loosen the sides of the springform pan and transfer to a cutting board.