Preheat the oven to 350℉. Grease doughnut tins with non-stick spray.

In a large bowl, whisk together the melted butter, oil, sugar, eggs, and vanilla until well combined. Add the sour cream and whipping cream and whisk until incorporated.

In another bowl, whisk together the flour, sifted cocoa powder, baking powder, baking soda, and salt. Pour the dry ingredient mixture into the bowl with the combined wet ingredients and stir just until no streaks or large lumps of flour remain. Do not overmix!

Transfer the batter to a Ziploc bag with the corner snipped off or a piping bag fitted with a wide tip. Pipe the batter into the prepared doughnut tin(s), filling each doughnut well about ½ full.

Bake in the preheated oven for 10-12 minutes or until a toothpick inserted into the center of the doughnut comes out clean. Let cool in the pans for 5 minutes before transferring to a wire rack to finish cooling completely before glazing or coating with powdered sugar. Bake the remaining doughnuts.

In a medium-sized bowl, whisk together the powdered sugar and sifted cocoa powder. Whisk in the whipping cream, 1 tablespoon at a time, until a smooth, pourable yet not too runny glaze consistency is reached. Adjust with more powdered sugar or whipping cream as needed. Dip the cooled doughnuts in the icing or drizzle the icing on top. Enjoy!