Preheat the oven to 425 degrees
1 pound bittersweet chocolate — * see note
1/2 pound unsalted butter
6 large eggs — * see note
8″ spring-form pan at least 2 1/2 inches high.
Butter and line the bottom with buttered parchment paper or wax paper.
Wrap a double layer of heavy-duty foil around the outside of the 8″ pan. Since we are baking this in a water bath, this is to prevent water from invading our batter.
Use a 10″ cake pan, or roasting pan to serve as a water bath (you will place the 8″ pan into this one)
In a large metal bowl set over a pan of hot, not simmering water (the bottom of the bowl should not touch the water) combine chocolate and butter and let stand, stirring occasionally until smooth and melted.
In a large bowl set over pan of simmering water, heat the eggs stirring constantly to avoid curdling until just warm to the touch.
Remove from heat, and beat using a whipping beater until triple in volume and soft peaks form when the beater is raised (about 5 minutes)
Using a large wire whisk or spatula fold half of the eggs into the chocolate mixture until almost incorporated.
fold in the remaining eggs until just blended and no streaks remain.
Finish by using a heavy spatula to ensure the heaver mixture at the bottom is incorporated.
Scrape into the prepared pan (the 8″ one) and smooth the top with a spatula.
Place 8″ spring form pan into larger water-bath pan and surround it with hot water until it comes up the sides of the spring-form pan 1 inch.
Bake 5 minutes and cover loosely with a piece of buttered foil, and bake 10 minutes.
The cake will look soft, but this is as it should be.
let cool 45 minutes on a rack
cover with plastic wrap, and refrigerate until very firm (about 3 hours).
Unmold by wiping sides of pan with hot damp cloth, then place onto plate
The cake can be stored up to two weeks refrigerated, but do NOT freeze, it will make the cake poopy.
* eggs: equaling 1 1/4 **scant** liquid cups
* chocolate: if using Tolbler extra bittersweet, add 3 tablespoons of sugar while beating eggs.