Melt butter over medium heat in a sauce pan
Just before butter is completely melted - add sugar. Stir until butter is completely melted and sugar is mixed evenly into the melted butter.
Transfer melted butter and sugar mixture into bowl. I use my KitchenAid Mixer
In same bowl, mix together butter/sugar mixture, salt, baking powder, vanilla extract, eggs, cocoa powder and flower. (I allow the mixer to run for a couple minutes - mixture will be thick)
When all above ingredients are mixed thoroughly - stir in chocolate chips.
IMMEDIATELY pour into greased 13x9 baking pan. (The longer you wait - the thicker and harder to transfer the mixture)
Bake at 350 for 23 minutes. Your oven may require a few more minutes. (I know that is an odd number - but it will continue to cook in the pan for a minute or two once it is removed from the oven. Overdone brownies are just not yummy!)