1. 1. Preheat the oven to 350°F (180°C).

2. 2. In a saucepan, heat whole milk until it's warm but not boiling.

3. 3. In a mixing bowl, whisk eggs and coarse sugar until well combined.

4. 4. Gradually pour the warm milk into the egg mixture while whisking continuously.

5. 5. Add butter and cocoa powder to the mixture and whisk until smooth.

6. 6. Pour the mixture into individual ramekins.

7. 7. Place the ramekins in a baking dish and fill the dish with hot water halfway up the sides of the ramekins.

8. 8. Bake in the preheated oven for 30-35 minutes or until the custard is set.

9. 9. Remove from the oven and let it cool before serving.

10. 10. Sprinkle with additional coarse sugar before serving, if desired.