Preheat oven to 350℉. Grease a 9 x 13-inch baking pan with flour spray. Set aside.
In a large bowl, combine cocoa and baking soda. Add 1/3 cup melted butter and mix until incorporated.
Add boiling water; stir until well blended. You may want to use a whisk for this part.
Stir in sugar, eggs, and remaining butter. Add flour, vanilla and salt. Stir in chocolate chips.
Pour into prepared baking pan and spread evenly. Bake 30-45 minutes at 350℉ or until brownies begin to pull away from the sides of the pan and a toothpick inserted in the center comes out clean. Cool in the pan on a wire rack. Cut before serving.