Preheat the oven to 180°C (356°F).
In a bowl, combine unsweetened cocoa powder and all-purpose flour.
Add sugar, baking powder, and salt, and mix well.
Beat the eggs and mix with milk.
Combine the dry and wet ingredients to make a batter.
Add butter to the batter and mix once more.
Pour the batter into a bread pan.
Bake in the preheated oven for 25 minutes.
Let cool and slice for serving.