Preheat the oven to 375°F.
In a stand mixer, beat together the butter, brown sugar, granulated sugar, sour cream and vanilla extract until the mixture is a shade lighter in color, nearly doubke in size and very fluffy. About 3-4 minutes.
Add the flour, baking powder and salt to the stand mixer and mix on the lowest setting until just combined.
Add the chocolate to the dough, reserving a few big chunks for topping the cookies.
Portion the cookies into equal 35 gram balls and place 2 inches apart on a parchment-lined baking sheet. Indent the balls in the center, creating a well, then add a few chunks of chocolate to the top of each.
Bake for 9-10 minutes. When the cookies are out of the oven, give them a few smacks on the counter to flatter them into evenly perfect discs.
Let cool to firm up (see notes), then enjoy!
