Instructions

To make the cake:

1. Preheat oven to 350°F. Generously butter the bottom and sides of a 9-inch springform pan. Line the bottom of the pan with parchment paper. Butter the parchment.
2. Place the chocolate in a microwave-safe bowl. Heat at half power in microwave in 30-second increments until the chocolate melts when stirred. Set aside to cool.
3. Using an electric mixer on medium-high speed, beat the butter and sugar until light and fluffy.
4. Reduce mixer speed to low. Add the egg yolks, one at a time, mixing well after each addition. Scrape down the sides of the bowl as needed.
5. Add the cooled chocolate and mix until combined. Mix in the vanilla.
6. In a large bowl, whisk the egg whites and salt to stiff peaks. Gently fold about 1 cup of the whipped whites into the chocolate mixture. Add the remaining egg whites and continue folding gently just until combined.
7. Transfer the batter to the prepared pan and smooth the top evenly.
8. Bake 30-35 minutes, or until the top of the cake is set. Do not overbake.
9. Transfer the pan to a wire rack to cool completely. Once it has cooled, use a thin knife to loosen the cake from the sides of the pan. Then, remove the sides of the pan.
10. Invert the cake onto a wire rack and peel off the parchment paper. Use another rack or a plate to flip the cake upright.

To make the ganache:

1. Place the chocolate in a large heatproof bowl. Set aside.
2. Combine the cream and corn syrup in a small saucepan. Bring to a boil over medium heat.
3. Remove the cream mixture from the heat and pour over the chocolate. Allow to sit for 2 minutes.
4. Slowly stir the cream mixture and chocolate until the chocolate has melted and the mixture is combined and smooth. Whisk for 2-3 minutes to cool the ganache slightly. Stir in the vanilla.
5. Place the cake on a wire rack, and place the rack on a parchment-lined baking sheet.
6. Pour about 3/4 cup of the ganache over the cake. Use an offset spatula to smooth and spread the ganache just to the edges of the cake. Place the cake in the freezer for 5 minutes to set the ganache.
7. Then, pour the remaining ganache over the cake, allowing the glaze to run down the sides of the cake. You can use an offset spatula to smooth the ganache evenly on the top and sides of the cake, or just let the ganache pour over the sides naturally.
8. Chill the cake for 2 hours, or until the ganache has set.
9. Serve and store at room temperature.