Preheat the oven to 350℉ and line your baking pan with parchment paper (or use cooking spray). Set aside.
In a medium bowl, sift the flour, cocoa powder, baking powder and salt together. Set aside.
In a large microwave-safe bowl, carefully melt the butter in the microwave.
Once melted, add sugar and water. Whisk together until smooth.
Add eggs one at a time, mixing each addition completely. Add vanilla. Scrape sides of bowl.
Carefully add in flour-cocoa mixture and stir until mixed.
Bake for 18-20 minutes, or until a toothpick inserted in the center comes out with just a few crumbs clinging to it.
Cool completely in the pan on a wire rack.
If baked in a 9x13” pan, cool completely before cutting.
When stored properly, brownies will last up to 3-5 days at room temperature or 2-3 months in the freezer.