10 ounces dark chocolate, coarsely chopped
7 ounces salted butter, cut into pieces
5 large room temperature eggs
1 cup sugar
Preheat the oven to 350F. Grease a 9-inch springform pan and dust it with cocoa powder, tapping out any excess (If your springform pan isn’t 100% water-tight, wrap the outside with aluminum foil, making sure it goes all the way up to the outer rim).
Melt the chocolate and butter in a double boiler, stirring occasionally, until smooth. Remove from heat.
In a large bowl, whisk together the eggs and sugar, then whisk in the melted chocolate mixture until smooth. (Go slowly so that you don’t end up cooking your eggs!)
Pour the batter into the prepared springform pan and cover the top of the pan tightly with aluminum foil. Put the springform pan into a larger baking pan, such as a roasting pan, then add enough hot water to the baking pan to come about halfway up to the outside of the cake pan.
Bake for 1 hour and 15 minutes.
You’ll know the cake is done when it feels set, kind of like chocolate pudding. If you gently touch the center, your finger should come away clean.
Lift the cake pan from the water bath and remove the foil. Let cake cool completely on a cooling rack.