Preheat oven to 350 degrees F (175 degrees C). Grease an 8x8-inch baking dish.
Stir cocoa powder and butter together in a saucepan over low heat until coconut oil has melted, about 5 minutes. Remove from heat and let cool.
Beat eggs, just like sugar, salt, and vanilla extract together in a bowl; stir in cocoa mixture. Whisk coconut flour into egg mixture until there are no lumps. Pour batter into prepared baking dish; sprinkle chocolate chips over top.
Bake in preheated oven until a toothpick inserted into the center come out clean, about 35 minutes.