(2 sticks) unsalted butter, plus more, at room temperature, for the pan
unsweetened cocoa powder, for the pan
all-purpose flour, spooned and leveled
stout beer (such as Guinness)
semisweet chocolate, chopped
packed dark brown sugar
- Heat oven to 350° F. Butter a 12-cup Bundt pan and dust with the cocoa powder, tapping out the excess. In a medium bowl, whisk together the flour, baking soda, and salt.
- In a small saucepan, combine the butter and stout. Cook over medium heat, stirring, until the butter is melted. Remove from heat, add 8 ounces of the chocolate, and whisk until smooth.
- Using an electric mixer, beat the eggs and sugars on medium-high until fluffy. Beat in the chocolate mixture and sour cream. Reduce speed to low and gradually mix in the flour mixture until just combined (do not overmix).
- Pour into the prepared pan and bake until a toothpick inserted in the center comes out with a few moist crumbs attached, 45 to 55 minutes. Let cool 30 minutes in the pan, then invert onto a rack to cool completely.
- In a small saucepan, bring the heavy cream just to a boil. Remove from heat, add the remaining 4 ounces of chocolate, and let sit 5 minutes. Whisk until smooth. Set the cooling rack with the cake over a baking sheet. Drizzle the cake with the glaze and let set before serving.