Preheat the oven to 350 degrees and place silicone doughnut rings on baking trays for support. Spray the doughnut rings with oil if needed.
In a large mixing bowl, combine the flour, cocoa powder, sugar, chocolate chips, baking soda, and salt with a large spoon.
Combine the heavy cream, canola oil, and eggs in a medium mixing bowl, use a fork to beat them together.
Add the wet ingredients to the dry ingredients, stirring with a large spoon until fully combined. Transfer the batter to a piping bag or use a spoon to fill the doughnut molds.
Bake for 15 minutes. Remove from the oven and allow the doughnuts to cool for 10 minutes before carefully releasing them from the molds.
Dip the doughnuts into the Mocha Glaze or spoon the glaze on top of the doughnuts. Rest the doughnuts flat side down on a cooling rack. Decorate as desired while the glaze is still wet.
Doughnuts are best the first day. Leftovers can be stored at room temperature, loosely covered for 3 days.
Mocha Glaze:
Combine the chocolate chips, espresso powder, and corn syrup in a wide, medium bowl.
Heat the heavy cream in the microwave until it barely begins to boil. Carefully pour it over the chocolate chip mixture. Gently stir with a spoon while the chocolate melts and the ingredients combine into a smooth glaze. Allow to cool to the touch before dipping the doughnuts into the glaze.