Line a 9x13 baking dish with parchment paper. This will make for easy cleanup and easy removal from the pan for cutting. You can also grease your pan if you prefer.
In a small saucepan (low heat), melt the butter and add the sugar. Whisk together until the butter is fully melted and the sugar is blended. Remove from the heat.
Pour the melted butter and sugar into a bowl (make sure it is one that won't melt). Stir in eggs, stirring the entire time. Add the vanilla and stir.
Stir in the cocoa powder, salt, baking powder and flour. Stir only until combined, do not overmix. Add the chocolate chips and stir again, making sure to not overmix.
Pour into your 9x13 pan. (If you do not use parchment paper in it, make sure you grease it).
Place the pan in the oven, and let bake 30-40 minutes (depending on your oven). They are done when a toothpick comes out clean when poked in the center. Do not overbake- they are so much better a bit underdone I think!
Let them cool for at least 10 minutes. Pull the parchment paper out, carefully lifting the brownies from the pan (leave them on the parchment paper). Cut into squares.
If covered, they will stay soft and fresh for 4-5 days. You can always pop them in the microwave for a few seconds to get them warm again when re-serving. They are just as yummy as freshly baked. We eat brownie sundaes with them and reheat the brownie the next day before adding the ice cream and chocolate sauce.
Nutrition information is automatically calculated and should only be used as an approximation.