Preheat oven to 325 degrees F (162 C). No fan.
Place 4 ramekins into a baking dish with 2” sides.
In a medium size bowl, add yolks. Add ½ cup sugar to yolks, whisk well.
In a medium sauce pot, heat cream and buttermilk together. Once warm, add the cocoa powder, vanilla, and red food color. Whisk lightly until smooth.
Once cream mixture is hot (do not boil), temper cream with yolk mixture. You’re slowly heating up the yolk mixture with the hot cream as to not curdle. Once you’ve tempered in the yolks, divide evenly into ramekins. (Do not return to pot after you’ve tempered in the yolks because you’re not trying to cook the yolks over the stove)
If you’ve got bubbles on the top of the mixture, lightly torch the surfaces to remove.
Fill up the baking dish with hot water, cover loosely with tin foil, and poke some holes in the foil to vent.
Carefully place dish in the middle of your oven.
Bake for 40 minutes. To check whether it is done, jiggle the dish a little and if the center seems loose, bake a little longer, checking every 5 minutes.
Once baked, remove from oven and carefully place each ramekin on a cookie sheet.
Refrigerate for 4+ hours, or overnight. The custard should be served chilled.
When serving, sprinkle about 1 T of sugar over the top of the custard, and shake to even out. Use a blowtorch to brulee each ramekin. Another way to brulee without using a torch is to set your oven on broil, sprinkle the sugar over each custard, and broil for about 3-5 minutes.