Guinness Stout Cake by Brian Hart Hoffman | Williams Sonoma

Ingredients

• 1 1/2 cups (300 g) granulated sugar
• 1 1/2 cups (188 g) all-purpose flour
• 1/2 cup (43 g) unsweetened cocoa powder
• 1 tsp. (5 g) baking soda
• 1 tsp. (5 g) baking powder
• 1 tsp. (3 g) kosher salt
• 1 cup (240 g) whole buttermilk
• 6 Tbs. (84 g) vegetable oil
• 1 large egg, lightly beaten
• 1 large egg yolk
• 3/4 tsp. vanilla extract
• 3/4 cup (180 g) boiling stout beer, such as Guinness Extra Stout
• 1 cup (250 ml) water
• 1 Tbs. light corn syrup
• 1/4 tsp. (0.50 g) cream of tartar
• 1/3 cup (76 g) unsalted butter, softened
• 3/4 cup (180 ml) heavy whipping cream, warmed
• 2 Tbs. bourbon
• 1/2 tsp. vanilla extract
• 1/4 tsp. (0.75 g) kosher salt
• 4 large egg whites, room temperature
• 1/2 tsp. (1 g) cream of tartar
• 3/4 cup (150 g) castor sugar