Sift the flour, cocoa powder, and cornstarch into the bowl of a stand mixer. Add the sugar, baking powder, salt, egg, milk, vanilla, and oil and whisk together.
Scrape batter into a zip top bag. Snip off the end and pipe batter into wells greased (or nonstick) donut pans (fill about halfway).
Bake at 450º for 7-9 minutes, until donut springs back when pressed. Let cool.
Meanwhile, pour the chocolate chips into a small bowl. Pour creamer over the chocolate chips until just barely level (I like to use just a little less so that the ganache is thicker). Microwave for 1 minute, and then whisk until a smooth ganache forms.
Dip the tops of the donuts in the ganache while ganache is warm, or spread over top of the donuts with a spoon.
