Preheat oven to 350 degrees.
Line an 8x8 baking dish with aluminum foil and let the edges hang off the sides and coat with non stick spray.
Add chocolate chips to a small bowl and microwave for 45 seconds. Stir, then microwave for another 15 seconds.
Stir until smooth then set aside to cool.
In a large bowl add eggs and butter and beat until smooth.
Add eggs then vanilla and mix well.
In a separate bowl add the dry ingredients: flour, salt, and cocoa.
Whisk to combine and sift to get out any extra clumps. Then slowly mix into the wet ingredients.
Finally stir in the melted chocolate and mix well.
Pour into the greased pan and smooth the top.
Bake for about 25 minutes. Let cool completely before frosting with marshmallow topping.