Preheat the oven to 350°F. Spray two donut pan with baking nonstick spray.
In a large bowl, mix the flour, black cocoa powder, Oreo crumbs, baking powder, baking soda, and salt. Set aside.
1 cup All-purpose flour, ½ cup Black cocoa powder, ½ cup Oreo crumbs, ½ teaspoon Baking powder, ½ teaspoon Baking soda, ½ teaspoon Salt
In a medium bowl, mix the eggs, vanilla, sugar, buttermilk, and melted butter (needs to be cooled to room temperature first). Pour the wet ingredients on top of the dry and mix until just combined.
2 Large eggs, 1 teaspoon Pure vanilla extract, ¾ cup White granulated sugar, ½ cup Buttermilk, 5 tablespoon Unsalted butter
Pour the batter into a piping bag and cut off the end. Pipe the cake batter into the donut pan about ½ full.
Bake for 10-15 minutes until a toothpick inserted comes out clean. Let them sit in the hot pans for 10 minutes before transferring to a cooling rack to cool completely.