Butter and flour a 9" square baking pan. Set aside
Preheat your oven to 350 degrees F.
Melt half the butter and pour into a small mixing bowl. Let cool to room temperature. Add the remaining butter and whisk until creamy and there is just few bits of butter left.
In a large mixing bowl of your stand mixer, beat together eggs and sugar until pale and thick. Mix in vanilla extract.
Alternating with butter, add the dry ingredients in 3 parts ( dry, butter, dry, butter, dry, butter ).
Stir in chocolate chips. At this point the batter can be covered and refrigerated for up to a week.
When ready to bake, spread the batter in prepared pan. The batter will be thick. Smooth the top with a spatula.
Bake 40to 45 minutes, until the toothpick test shows only few crumbs.
Cool in pan to room temperature.
Dust with powdered sugar and cut into squares.
Notes
I baked these brownies in a 13"x9" pan and they came out great. I recommend checking on them after the 30 minute mark. Test with toothpick. I skipped the chocolate chips simply because I wanted to focus on the texture of the brownies, but feel free to add them.