01 - Preheat the oven to 350°F. Lightly grease a donut pan with butter or nonstick spray.
02 - In a large bowl, whisk together flour, cocoa powder, sugar, baking powder, baking soda, and salt until evenly mixed.
03 - In a separate bowl, beat the eggs then add milk, melted butter, and vanilla extract. Stir until fully incorporated.
04 - Add wet ingredients to dry ingredients and gently mix until just combined. Avoid overmixing to maintain light texture.
05 - Transfer batter into a piping bag or resealable plastic bag, then pipe evenly into the donut cavities, filling each about three-quarters full.
06 - Bake for 10 to 12 minutes or until a toothpick inserted into a donut comes out clean.
07 - Allow donuts to cool in the pan for 5 minutes before transferring them to a wire rack to cool completely.
08 - Whisk together powdered sugar, cocoa powder, milk, and vanilla extract until smooth.
09 - Dip cooled donuts into the glaze, letting excess drip off. Place on wire rack until the glaze sets.