Preheat the oven to 180°C or 350°F. Spray your doughnut pan with non-stick spray. Set aside.
In a large bowl, mix together the flour, cocoa powder, sugar, espresso powder, baking powder and salt.
In a separate bowl, mix all the remaining wet ingredients – the milk, butter and egg – until you have a creamy consistency.
Add the wet mixture to the dry mixture gently. Mix them together until everything is combined.
Transfer the mixture to a piping bag and pipe the batter into the pan, filling about halfway.
Bake the doughnuts for 10 minutes, until they're fully cooked from the inside and a cake tester comes out clean.
Allow them to cool for few minutes in the pan before placing them on a cooling rack. Let them cool completely.
For the glaze, you can either place the chocolate, heavy cream and butter in a small bowl and gently melt everything in the microwave with 30 seconds intervals. Or else, in a small saucepan you can heat up the heavy cream and butter, then place the warm liquids on top of the chopped chocolate in a bowl. Mix together until all the chocolate has melted.
Dip the doughnuts in the glaze and place them back on the cooling rack, for the extra glaze to drip off. The doughnuts can be enjoyed immediately or after the glaze have set. Enjoy!