Preheat your oven to 350°F (175°C).
Grease and flour your cake pan.
In a large bowl, combine the flour, sugar, cocoa powder, baking powder, baking soda, and salt.
Add the eggs, milk, oil, and vanilla extract. Mix until smooth.
Stir in the boiling water. The batter will be thin.
Pour the batter into the prepared pan.
Bake for 30-35 minutes, or until a toothpick inserted into the center comes out clean.
Let the cake cool in the pan for 10 minutes, then remove to a wire rack to cool completely.