Preheat oven to 350 degrees. In a large mixing bowl (that fits in your microwave) melt 1¼ stick butter. In a separate bowl, whisk together the flour, salt, baking powder and baking soda and set aside. Thoroughly grease a 9×13 pan.
Stir together the melted butter and brown sugar until smooth. Add eggs and vanilla to the butter mixture, and stir again. Slowly add the dry ingredients to the wet ingredients and stir to combine. Add the chocolate chips and stir well.
Pour batter into a well-greased 9×13 pan and bake for 23-25 minutes. They should be slightly browned along the edges and about a brownie consistency in the center. Cool them in the pan and then remove to wire rack; cool completely before storing them in an airtight container.