Line a muffin tin with cupcake liners and preheat the oven to 350°F.
In a large bowl, mix together sugars, vanilla extract, and melted butter.
Beat in eggs, one at a time.
Mix in salt, baking soda, and baking powder.
Sift and mix in the cocoa powder.
Mix in the buttermilk.
Mix in the flour.
Spoon the batter evenly into the cupcake liners and bake for ~30min or until a toothpick comes out clean.