Preheat the oven to 350 degrees F. Grease a donut pan or two and set them aside.
In a medium bowl, whisk together the flour, sugars, cocoa powder, baking soda, and salt. Set aside.
In another medium bowl, combine the buttermilk, eggs, melted butter, yogurt, apple cider vinegar, and vanilla extract. Mix until just combined.
Add the wet ingredients to the dry and mix until just combined.
Spoon or pipe the batter into the donut pan molds ~¾ of the way full. Bake 18-20 minutes, or until a toothpick, when inserted into a donut, comes out clean.
Allow the donuts to cool for 5 minutes in the pan before removing them to a wire rack to finish cooling completely.