
Preheat the oven to 350°F.
In a medium heatproof mixing bowl, add the chocolate, cocoa powder, and espresso powder.
Pour hot water over mixture. Cover and let stand for 5 minutes.
Whisk the mixture gently until smooth, then set aside to cool until just warm (95-98°F).
In a large bowl, whisk together the brown sugar, flour, salt, and baking soda, breaking up any clumps.
Whisk the sour cream, oil, eggs, and vanilla into the cooled chocolate mixture until smooth.
Making a well, pour the wet mixture into the center of the dry flour mixture and use a spatula to gently fold ingredients together until just combined and no flour pockets remain. Do not overmix.
Spray a 12-cup Bundt cake pan generously with Baker’s Joy or brush with melted shortening, using a pastry brush to brush the spray or shortening into every nook and cranny of the pan. Immediately pour the cake batter into the prepared bundt pan.
Bake the cake for 50-55 minutes, or until a toothpick comes out with moist crumbs.
Let the cake cool on a wire rack for 10 minutes, then turn it out onto a platter and let it cool completely. If your cake doesn’t release, run a thin spatula around the inner tube to help.
In a small saucepan, heat the cream and corn syrup over medium heat until hot.
Remove from heat and add the chocolate, whisking until smooth. Let cool until thickened.
Drizzle over the cake. Allow to set at room temperature for about 10 minutes before serving. For an extra fudgy cake, serve chilled.