Lightly grease a 9x13 pan and line with parchemnt paper. Preheat oven to 350 degrees.In a medium bowl combine flour, sugar, cocoa powder, salt, baking powder and baking soda then set aside.
In a large bowl add the eggs, milk, oil, and vanilla then use an electric hand mixer to fully combine.
Now add the dry ingredients into the wet ingredients then use a hand mixer to incorporate all the ingredients together. Add the cup of hot water and mix one more time until well combined and cake batter is slightly runny.
Pour the cake batter into the prepared baking pan and place in preheated oven to bake, about 30-35 minutes. Allow cake to cool before adding frosting, or decorating.
This cake will last about a week at room temperature, and can also be wrapped in plastic wrap and frozen for up to 3 months.