Preheat oven to 350°F. Grease a donut pan with oil or butter; set aside.

Make the donuts: In a large bowl, whisk together flour, cocoa powder, baking powder, baking soda, salt, espresso powder, and chocolate chips. Set aside.

In a separate bowl, whisk the egg with brown sugar until well mixed. Add the milk, sour cream, melted butter, vanilla, and vinegar; whisk to combine.

Add the flour mixture to the egg mixture and stir until just combined. The batter will be thick. Using a spatula, transfer the batter to a piping bag or zip-top plastic bag. If you don't have either, a spoon will do just fine! Cut off the tip of the piping bag or plastic bag and fill donut cavities with batter until 3/4 full.

Bake for 12-15 minutes or until a toothpick inserted into the center of the donuts comes out clean. Let the donuts cool in the pan for 5 minutes before transferring to a wire rack to cool completely.

Make the chocolate glaze: Microwave the chocolate, cream, and butter in 30-second intervals, stirring in between until melted. Or use a double boiler and melt the chocolate, stirring until smooth. Once the donuts are completely cool (this only takes a few minutes), dip the tops of the donuts into the chocolate glaze and place them on a rack to set. While the chocolate is still wet, add sprinkles or other decorations to the top.