- 4 eggs
- 8 oz bittersweet chocolate coarsely chopped (you can use semisweet if you prefer a sweeter chocolate)
- 8 tbsp (1 stick) unsalted butter, cut into small pieces
- Adjust an oven rack to the lower-middle position and heat the oven to 325 degrees. Line the bottom of an 6 or 7-inch springform pan with parchment paper or waxed paper and grease the sides of the pan. Wrap the outside of the pan with 2 sheets of heavy-duty aluminum foil and set it in a large roasting pan. Bring a kettle or pot of water to boil.
- In a stand mixer using the whisk attachment, beat the eggs at high speed until the volume doubles (about 5 minutes).
- Meanwhile, melt the chocolate and butter together. I put them in a glass bowl and put it in the microwave for 30 second intervals, stirring in between until the mixture is melted and smooth. Then fold about a third of the beaten eggs into the chocolate mixture using a large rubber spatula until no streaks of egg are visible. Then fold in another third of the egg mixture, and then the last third of the egg mixture.
- Scrape the batter into the prepared springform pan and smooth the surface with a rubber spatula. Place the roasting pan on the oven rack and pour in enough boiling water to come about halfway up the sides of the springform pan. Bake until a toothpick inserted comes out clean, about 20-25 minutes. Remove the springform pan from the water bath and set on a wire rack; cool to room temperature.
Recipe adapted from Gimme Some Oven who adapted it from Cook's Illustrated