Preheat your oven to 350°F (175°C) and grease a sheet pan.
In a large mixing bowl, sift together flour, sugar, cocoa powder, baking powder, baking soda, and salt.
Add eggs, milk, oil, and vanilla extract to the dry ingredients.
Beat on medium speed for about 2 minutes until smooth.
Carefully stir in the boiling water; the batter will be thin.
Pour the batter into the prepared sheet pan.
Bake for 30-35 minutes or until a toothpick comes out clean.
Remove from the oven and let it cool completely in the pan.
Frost with chocolate frosting once cooled.
Slice and serve, garnishing with fresh berries if desired.