Preheat oven to 350°F. Lightly spray two 9" round baking pans with cooking oil spray and then line with parchment paper.
In a small bowl, whisk the cocoa powder with the boiling water until smooth and set aside.
Use a spatula to combine the flour, sugar, baking powder, baking soda and salt in a medium mixing bowl. Add the milk, vegetable oil, eggs, vanilla and stir until fully incorporated. Slowly pour in the water/cocoa mixture and stir until blended. (Do not over mix.)
Fill the two round baking pans with equal amounts of batter and then add the baking melts in a single layer, making sure to distribute them evenly in the pans.
Bake for 30-35 minutes. Rest for 15 minutes before transferring them to a cooling rack to cool completely.