Line a cupcake or muffin pan with 12 paper baking cups.
Put eggs, sugar and oil in a bowl and mix until combined.
Add the milk and mix until combined.
Add the flour, cocoa powder, baking powder, baking soda and salt and mix until combined.
Divide the batter between 12 paper cupcake cups.
Put the cupcakes in the oven and bake for 18 minutes.
Remove the cupcakes from the oven and let cool completely before frosting.
Put frosting in a piping bag fitted with a tip of your choice and frost the cupcakes (if you don't have a piping bag, put frosting in a ziploc bag, cut off one corner of the bag and squeeze the frosting onto the cupcakes).