Preheat oven to 350°F (175°C) and grease a donut pan.
In a bowl, whisk together flour, cocoa powder, sugar, baking powder, baking soda, and salt.
In a separate bowl, mix eggs, milk, vegetable oil, and vanilla extract until combined.
Combine wet ingredients with dry and whisk until smooth without overmixing.
Spoon or pipe the batter into the donut pan, filling each mold about three-quarters full.
Bake donuts for 12 to 15 minutes, then allow to cool in the pan briefly before removing.
Heat heavy cream until warm but not boiling, then pour over chocolate chips and stir until smooth to create the glaze.
Dip cooled donuts into the chocolate glaze and add optional toppings as desired.
Allow glaze to set slightly before serving.