Preheat oven to 325 degrees. Line a 8x8 or 9x9 pan with parchment paper. This step is optional, but it makes it so much easier to remove the brownies when they are baked.
Melt your chocolate and butter. This can either be done in the microwave or a heatproof bowl over a double boiler. Mix until it is pretty smooth and set it aside.
Combine the flour, cocoa powder, baking powder, and salt. Mix them well and set them aside as well.
Beat the eggs on medium speed with a hand mixer or stand mixer for about 3 minutes. They should be light and fluffy.
To the egg mixture, add the granulated sugar and brown sugar. Mix for 1 minute on medium speed.
Pour the melted chocolate/butter mixture and the milk. Mix until it is combined.
Last are the dry ingredients. Mix this until it is combined.
Pour batter into your prepared baking pan (be sure to use a rubber spatula to get all the batter out) and sprinkle with the flake salt.
Move to the preheated oven and bake for about 35-45 minutes. Check for doneness- remember we don't want to overbake. In fact, the chocolatey brownies are the ones that are just slightly underbaked. There should be a very slight wobble in the brownies when they are done baking.