Preheat your oven to 350 degrees and grease a 9x13 pan.
First, combine cocoa powder and baking soda in a large bowl. Stir in half of the butter (1/3 cup), then the water, and stir until the mixture thickens.
After your mixture thickens, stir in sugar, eggs (one at a time), and remaining butter (1/3 cup) until smooth.
Add the flour, vanilla, and salt to the batter and stir until combined. Finally, stir in the chocolate chips.
Pour batter into pan and bake for 30 minutes.