Preheat the oven to 400°F (200°C). Lightly grease a mini donut pan with nonstick cooking spray.

In a medium bowl, whisk together the flour, cocoa powder, baking powder, and salt.

In another bowl, whisk the eggs, sugar, buttermilk, and melted butter until smooth.

Add the wet ingredients to the dry ingredients and stir just until combined.

Transfer the batter to a piping bag fitted with a ½-inch round tip.

Pipe a thin layer of batter into each donut cavity, filling each about halfway.

Bake the Mini Chocolate Donuts for 4–6 minutes, or until they spring back when gently pressed.

Allow the donuts to cool in the pan for 5 minutes before transferring them to a wire rack.

To prepare the ganache, heat the heavy cream until it begins to simmer.

Pour the hot cream over the chopped chocolate and whisk until smooth.

Let the ganache cool slightly until it thickens.

Dip each cooled donut into the ganache.

Decorate with sprinkles while the glaze is still wet.

Serve immediately for the freshest flavor.