Preheat oven to 325 degrees F.
Place 6 (7 to 8-ounce) ramekins into a roasting pan.
Add the eggs to a large bowl, add 1/2 cup of sugar, salt and whisk until well mixed. Stop to scrape the sides and bottom of the bowl.
Add cocoa powder, and whisk to combine. Scrape the sides and bottom of the bowl and whisk again until fully combined. Set aside.
Add chopped chocolate to a medium bowl.
Add heavy cream to a medium sauce pan, stir and heat it until hot, and it simmers lightly, do not boil. Remove from heat.
Pour the hot cream over the chopped chocolate and let sit for 1 minute. Stir with a spatula until the chocolate is fully melted, the mixture should be combined, smooth and shiny. Stir in vanilla extract.
With the mixer on low speed, gradually add the chocolate mixture to the egg mixture, slowly mixing continually. Add the cream little by little, especially at the beginning, otherwise it may cook some parts of the egg mixture.
Use a spoon to scoop and discard the foam accumulated on top of the custard mixture.
Pour the custard mixture into the prepared ramekins.
Pour hot water into the pan to come roughly halfway up the sides of the ramekins.
Bake in the preheated oven for 45 - 50 minutes. The crème brûlée is done when it looks set, but still just slightly jiggly in the middle.
Once cooked, remove the roasting pan from the oven and let the creme brûlée cool in the pan before transferring to the fridge.
Cover the ramekins with plastic wrap and refrigerate for at least 2 hours and up to 3 days.
When ready to serve, remove the crème brûlée from the refrigerator, 30 minutes before browning the sugar on top. Sprinkle a tablespoon of fine sugar on top of each serving. Using a torch, melt the sugar to form a crispy top.
If you don’t have a torch, broil the crème brûlée to melt the sugar. Keep an eye on it, to make sure it doesn't burn.
Allow the crème brûlée to sit for 10 minutes before serving.