2 1/2 cups heavy cream
6 tablespoons (3/4 stick) unsalted butter cut into pieces
1 vanilla bean
7 ounces dark chocolate (70 to 80 percent cacao)roughly chopped
2 cups light corn syrup, preferably Lyle’s Golden Syrup
2 cups granulated sugar
2 cups Dutch process unsweetened cocoa powder,sifted
1/4 teaspoon kosher salt
Makes enough frosting for one double layer cake
In a medium saucepan, combine the cream, and butter. Slit the vanilla bean in half lengthwise, scrape out the seeds and add along with the scraped pods to the cream in the saucepan. Stir over medium heat until everything is melted.
Remove and discard he vanilla bean pod and stir in the chopped chocolate until it’s completely melted. Add the cocoa powder, sugar, salt, and syrup and whisk until the mixture is smooth. Transfer the frosting to a bowl, cover, and refrigerate until it’s cool and thickened, 1 to 2 hours or overnight.
Before icing the cake, let the frosting sit at room temperature until it’s spreadable.