Put the cocoa, chocolate pieces, and espresso in a large bowl. Pour over the boiling water and cover with a plate. Let it stand for 5 minutes. Meanwhile, in another bowl whisk together the flour, baking soda, and salt.

Whisk the chocolate mixture until it is smooth and set aside until it comes to room temperature.

When it has cooled, whisk in the sour cream.

Using either a hand mixer, or a stand mixer cream together the butter, brown sugar, and vanilla for about 5 minutes until pale and fluffy.

Add the eggs one at a time scraping the bowl after each egg.

Turn the mixer to low and add one third of the flour mixture to the bowl.

Add half of the chocolate mixture and repeat until all is incorporated. You will have three flour additions and two chocolate ones.

Pour the batter into the Bundt pan that has been either sprayed well with cooking spray (like the Bakers Joy kind with flour) or coated well with butter.

Bake the cake in a preheated 350 degree oven with the rack in the lower middle position. Bake for 50 to 60 minutes and rotate once during baking. A toothpick should come out with moist crumbs. Let cool on a rack for 10 minutes, then turn the cake out and let cool completely.

To make the glaze, whisk together 1 3/4 cups confectioners sugar, 1/4 cup milk, and 1/4 teaspoon vanilla or almond extract, and a pinch of salt.

Pour the glaze over the cooled cake and let it set.