Add cocoa powder, sugar, chocolate chunks, and sea salt in a small bowl. No need to mix together.
Bring milk to a boil on medium heat in a heavy bottomed pot.
Lower heat to low.
Add in cocoa mix and vanilla extract. Vigorously whisk until all chocolate is melted and dissolved. Turn off the stove.
It will make your kitchen smell really good. Taste and add more sugar if you need it.
Top with homemade with whipped cream (optional).