In a bowl, combine the flour, sugar, cocoa powder, baking powder, baking soda, and salt, sifting them together. Mix on low speed with a mixer.

Add the milk, butter, and vanilla extract. Beat on low speed, then beat for 2 minutes on medium speed. Add the egg and beat for 2 more minutes. Pour the batter into a greased and floured 9-inch (22 cm) round cake pan.

Bake at 350°F for 30-35 minutes. Remove from the oven and let cool for 10 minutes.

Remove from the pan and let cool completely. Sprinkle sugar on top to decorate. Enjoy.