Preheat your oven to 350 degrees F. and prepare three 8-inch cake pans by spraying generously with non-stick spray and line the bottom with a circle of parchment paper and set aside.
In a stand mixer equipped with a whisk attachment, add the flour, sugar, cocoa powder, baking soda, baking powder, and salt. Whisk to combine.
In a medium bowl or liquid measuring glass, add the eggs, milk, vegetable oil, and vanilla and whisk to combine. With the mixer on low speed, slowly pour the liquid into the dry ingredients and mix until combined. Scrape the sides and bottom of the bowl.
Last, carefully pour in the hot water and mix on low speed until combined. Increase to high speed for about one minute.
Divide the batter evenly between the three prepared cake pans and bake for 20-23 minutes until a toothpick inserted in the center of each cake comes out clean.
Remove from the oven and allow the cakes to cool in the pans for 10 minutes then flip onto a wire rack to cool completely.
Once the cakes are cool, you can wrap them in plastic wrap and refrigerate them until you are ready to assemble. I recommend chilling your cakes for at least an hour to make them easier to assemble, however it is not required.