Preheat oven to 350°F and spray a 9x5-inch loaf pan with baking spray. Line pan with parchment paper and leave a few inches of overhang on each side for easy removal after baking.
In a microwave safe bowl, add butter and chocolate chips. Microwave in 30 second intervals, stirring well after each, until melted and smooth.
Add sugar and mix on medium speed with an electric mixer well until combined. Add flour, cocoa powder, salt, egg, vanilla, and water. Fold ingredients together until just combined; do not over mix—a few lumps are okay.
Pour batter into pan and sprinkle with additional chocolate chips if desired.
Bake for 30 to 35 minutes or until firm around the edges and slightly crackled on top. A toothpick inserted into the center of the brownies should come out mostly clean. A few crumbs or chocolate smudges are okay.
Let brownies cool in pan and cut into pieces to serve.