Preheat your oven to 350°F (175°C). Grease and flour a 9-inch round cake pan, or line it with parchment paper for easy removal.
In a large mixing bowl, sift together the flour, sugar, cocoa powder, baking powder, baking soda, and salt. Mix well to combine.
In a medium bowl, whisk together the Miracle Whip, milk, eggs, and vanilla extract until smooth.
Gradually add the wet ingredients to the dry ingredients, mixing until just combined. Be careful not to overmix.
Stir in the boiling water until the batter is smooth. The batter will be quite thin, but this is expected.
Pour the batter into the prepared cake pan, spreading it evenly with a spatula.
Bake in the preheated oven for 30 to 35 minutes, or until a toothpick inserted into the center comes out clean.
Remove the cake from the oven and let it cool in the pan for 10 minutes before transferring it to a cooling rack to cool completely.
Frost and decorate as desired. A simple chocolate ganache or cream cheese frosting complements this cake beautifully.