Preheat the oven to 350°F (180°C) and spray a 9x13 baking dish with non-stick spray and line it with parchment paper so that there is overhang on either side. Set aside.
Sift all purpose flour and cocoa powder into a mixing bowl, add the salt and mix together.
Add the butter and ½ cup chocolate chips or chopped chocolate to a microwave safe bowl and microwave in 30-second intervals bringing it out to stir every 30-seconds until melted.
Add the sugar, eggs and vanilla in with the melted butter and chocolate and whisk in together until well mixed.
Add the wet ingredients in with the dry and mix into a thick batter.
Add the chocolate chips and fold in.
Transfer the batter to the prepared 9x13 dish and smooth down.
Add more chocolate chips directly to the top of the brownies (optional).
Place into the oven and bake for 30 minutes. You will know the brownies are done when they are dry and shiny on top and when a toothpick inserted into the center comes out with melted chocolate or moist crumbs but NO wet batter.
Let the brownies cool in the pan for 10 minutes before lifting them out with the parchment paper overhang. Let them cool completely before cutting into squares.