Pre-heat the oven to 350° F, and line muffin tin/s with cupcake liners.
In a large mixing bowl, whisk together the sugar, flour, and cocoa powder.
In a medium saucepan, bring the butter, oil, and water to a boil.
Then remove the mixture from the heat, and mix together with the flour mixture.
In a separate bowl, dissolve the baking soda in the buttermilk by whisking together for a minute or so.
Then beat the eggs in with that buttermilk mixture.
Add the egg mixture and vanilla extract to the flour mixture in the mixing bowl, and mix well.
Pour the cupcake batter into the prepared muffin pan/s, and bake at 350° for about 15-20 minutes, or until a toothpick inserted in the center of a cupcake comes out clean.
Let the cupcakes cool in the pan for about 10 minutes before removing to a wire rack to cool completely.