Preheat the oven to 325°F and line an 8x8-inch baking pan with parchment paper
In a medium bowl, whisk together dry ingredients:
1 cup sugar
3/4 cup flour
2/3 cup cocoa powder
1/2 cup powdered sugar
1/2 cup dark chocolate chips
3/4 teaspoon salt
In a large bowl, whisk together wet ingredients:
2 eggs
1/2 cup olive oil
2 tablespoons water
1/2 teaspoon vanilla extract
Srinkle dry ingredients over wet ingredients and stir until just combined
Pour batter into prepared pan and bake for 35 to 40 minutes, or until a toothpick inserted into the center comes out clean (lean on the side of underbaking)