Towering Flourless Chocolate Cake

INGREDIENTS

• 3 large egg whites
• 1/2 cup stout beer (such as Guinness)
• 3/4 cup turbinado sugar
• 6 large eggs
• 1 cup granulated sugar
• Pinch of salt
• 1 teaspoon vanilla extract
• 6 ounces unsweetened chocolate, chopped
• 2 tablespoons unsalted butter
• 2 ounces semisweet chocolate, chopped
• 1/4 teaspoon cream of tartar
• 6 ounces bittersweet chocolate, chopped
• 1 tablespoon light corn syrup
• 2 1/2 sticks unsalted butter, cut into pieces, plus more for the pan
• 2 teaspoons vanilla extract