Chocolate Cloud Cake

For the cake:

• Heat the oven to 350°F (175°C), and place the rack in the center.
• Line the bottom of an 9-inch (20cm) springform pan with parchment paper. (Do NOT butter the pan and parchment.)
• Fill a saucepan about 1/4 way with water, and place on stove. Set a heatproof bowl OVER the saucepan, making sure the bottom of the bowl is NOT touching the water.
• Add the chocolate to the bowl, and bring the water to a simmer. Gently whisk the chocolate occasionally to help it melt.
• When the chocolate is melted, remove bowl from the heat and whisk the butter in until the mixture is lovely and smooth.
• Take out 2 small bowls. Separate 4 of the eggs, placing 4 yolks in one bowl and 4 whites in the other bowl.
• In a large bowl, whisk 2 whole eggs and the 4 egg yolks with 1/2 cup of the sugar just until combined.
• Slowly whisk in the warm chocolate mixture into the egg mixture. And then whisk in the Cognac or Grand Marnier and the orange zest. Set aside.
• In the bowl of a stand mixer, beat the 4 egg whites until foamy, about 2 minutes. You can also use a hand mixer, if you don't have a stand mixer.
• Gradually add the remaining 1/2 cup sugar and beat until gorgeous glossy, soft peaks form that hold their shape but aren’t stiff, about 5 minutes more.
• Very VERY gently fold about a quarter of the beaten egg whites into the chocolate mixture to lighten it. This is the magic, so go slowly and carefully. Add 1/4 of the beaten egg whites at a time, being sure to fully incorporate before adding more. You want to be sure you don't see any of the whites. Continue to gently fold until the mixture is a lovely shade of milk chocolate, making sure there aren't any white streaks.
• Scrape the batter into the pan and smooth the top.
• Set the pan on a rimmed baking sheet and bake until the top is puffed and cracked and the center is no longer wobbly, 35 to 40 minutes. Be careful not to bake the cake beyond this point.
• Let the cake cool in the pan on a rack. Leave the cake in the springform pan.
• The center of the cake will sink as it cools, forming a sort of crater—this is a good thing, so don't worry!
• Let the cake cool completely.
• If you're making this a day ahead, store the cake at room temperature, keeping it in the springform pan. Do not top with the whipped cream yet! You want to wait to add the whipped cream until right before serving the cake.
• To make the whipped cream, whip the cream, confectioners’ sugar, and vanilla in a large bowl with a handheld mixer until soft—not stiff—peaks form.
• Using a spatula, fill the sunken center of the cake with the whipped cream, swirling the cream to the edges of the crater. Dust the top lightly with cocoa powder.
• Run the tip of a knife around the edge of the cake, carefully remove the sides of the pan, and cut into wedges to serve.
• Store any leftovers airtight in the refrigerator— if, by some chance, there are any. Whenever I've made this, people are literally liking the plate to get at the last crumbs.