Flourless Chocolate Cake with Meringue

Bahan-bahan (12 porsi)

• 12 tablespoons (1½ sticks) unsalted butter, plus more for greasing the pan
• 6 ounces semi-sweet chocolate, (best quality such as Ghiradelli, chopped)
• 1¼ cups sugar
• 5 large eggs
• ½ cup Dutch-process cocoa powder, (sifted (see note))
• 4 large egg whites
• 1/8 teaspoon cream of tartar
• ¾ cup sugar