Preheat oven to 325 degrees. Grease a 9x13 inch pan and line it with parchment paper.
In a small bowl, whisk together the flour, cocoa, baking powder and salt.
In a large bowl, whisk together the sugar, melted butter, and vanilla until combined. Add eggs to mixture, one at a time, until fully combined.
Combine the wet and dry mixture until just combined. Then fold in chocolate chips.
Pour batter into parchment lined pan and spread evenly.
Bake for 28-30 minutes, or until a toothpick comes out semi clean.
Cool completely and then cut into your preferred size squares.
