01 -
Preheat the oven to 350°Fahrenheit (175°C) and lightly grease three to four donut hole pans (depending on the size) or two 24-cup mini muffin pans.
02 -
In a large bowl, whisk the flour, cocoa powder, baking powder, baking soda, and salt until well mixed.
03 -
In a separate bowl, whisk the melted butter, granulated sugar, and brown sugar until thick and smooth. Blend in the eggs, yolk, and vanilla.
04 -
In a measuring glass, stir the milk and sour cream until smooth. Then, alternate adding the dry ingredients and milk to the wet, starting and ending with the dry. Stir gently by hand with a spatula just until no streaks of flour remain.
05 -
Use a mini cookie scoop or spoon to fill each muffin cup with batter until about 3/4 full.
06 -
Bake for about 10 minutes or until a toothpick inserted into the center comes out clean. Let the donut holes cool in the pans for a few minutes. Then, transfer them to a wire rack to cool completely.
07 -
Add the powdered sugar, 3 tablespoons of milk, and vanilla to a medium bowl. Whisk until smooth, adding more milk, as needed, to reach a pourable consistency.
08 -
Once the donut holes have cooled, dip each into the glaze, letting any excess drip off. Place the glazed donut holes back on the wire rack to set. If desired, thin the glaze slightly and re-dip the donuts 1-2 more times for a more pronounced finish.
09 -
Once the glaze has fully set, your baked chocolate donut holes are ready to enjoy!