While cooling, mill your flour, and mix with, baking powder, baking soda, and salt into a medium bowl. Set aside.
Once the brown butter is cooled, add it to a large bowl along with the granulated sugar and brown sugar. Whisk to combine.
Beat in the eggs, one at a time, until combined.
Then, add in the sourdough discard, greek yogurt, and vanilla. Whisk until combined and smooth.
Add the dry ingredient mixture to the wet and mix until just combined (make sure not to overmix).