• Adjust an oven rack to the middle of the oven and preheat the oven to 350F [180C]. Grease an 8 in [20 cm] loaf pan and line with a parchment sling.
• In a large bowl, whisk together the brown sugar, sour cream, oil, cocoa powder, eggs, vanilla, baking soda, baking powder, and salt until completely combined. Add the flour and use a rubber spatula to stir it in into the batter. Pour the hot coffee over the cake batter and gently mix it until incorporated. Add the chopped chocolate and mix again until combined.
• Pour the batter into the prepared pan, then bake for 42 to 50 minutes, until a wooden skewer or toothpick comes out with the tiniest bit of crumb. Transfer the cake to a wire rack and let cool for 20 minutes.

Chocolate Glaze

• While the cake is cooling, make the chocolate glaze: Place the chocolate in a small bowl. Heat the heavy cream in a small saucepan until it is simmering and just about to boil. Pour the cream over the chocolate, cover the bowl with plastic wrap, and let sit for 5 minutes. Remove the plastic wrap and use a butter knife to stir the chocolate into the cream, until it is completely smooth.
• Pour the glaze evenly over the cake and let the glaze set. Once set, use the parchment sling to remove the cake from the pan, then remove the parchment paper and let the cake cool completely. Slice and serve. The cake can be stored wrapped in plastic in the refrigerator for 2 or 3 days.