01 -
Position a rack in the center of the oven and preheat to 350°F (175°C). Thoroughly butter and flour a 10 or 12-cup Bundt pan, ensuring all surfaces are coated. Set aside.
02 -
In a small saucepan, combine the butter, cocoa powder, salt, and water. Place over medium heat and cook, stirring frequently, just until melted and combined. Remove from heat and set aside to cool slightly.
03 -
In a large bowl, whisk together the flour, sugar, and baking soda. Add half of the melted butter mixture and whisk until completely blended (the mixture will be thick). Add the remaining butter mixture and whisk until combined. Add the eggs one at a time, whisking until fully incorporated after each addition. Whisk in the sour cream (or Greek yogurt) and vanilla extract until the batter is smooth.
04 -
Pour the batter into the prepared Bundt pan and smooth the top. Bake until a toothpick inserted into the center of the cake comes out clean, about 40-45 minutes. Let the cake cool in the pan for 15 minutes, then invert onto a wire cooling rack. Allow to cool completely before glazing.
05 -
While the cake is cooling, prepare the glaze. Place the chopped bittersweet chocolate and corn syrup (or agave) in a medium bowl. In a small saucepan, combine the heavy cream and sugar. Heat over medium heat, stirring until the cream is hot and the sugar is dissolved. Pour the hot cream mixture over the chocolate and whisk until smooth and glossy.
06 -
Once the cake has completely cooled, generously drizzle the chocolate glaze over the top, allowing it to run down the sides of the cake. Let the glaze set for a few minutes before slicing and serving.