Steps
1. Preheat the oven to 350°F (175°C).
2. In a medium-sized bowl, use a whisk to mix together the butter, sugar, cocoa powder and all-purpose flour.
3. Grease a single-serving oven-safe dish.
4. Pour the cake batter into the oven-safe dish.
5. Bake in the oven for 8 minutes.
6. Let the cake cool and enjoy!