Prepare the Pan and the Ingredients

1. Butter the inside of the Springform Pan. Place a round of parchment paper the size of the pan bottom into the pan, and butter the parchment.  Double Wrap the buttered pan in foil, making sure it is watertight, and place it inside a larger pan, such as a roasting pan, or a larger round pan if you happen to have one.
2. Chop the chocolate into small pieces, and the butter into tablespoon-sized chunks.
3. Preheat oven to 425F or 400F for Convection.

Prepare the Cake Batter

1. Heat water in a large (4 qt.) saucepan to simmer on the stove.  Place the butter and chocolate into the pan and let them melt. Stir occasionally. This can also be accomplished in a large bowl in the microwave, stirring every 20 seconds until melted. Stir until combined.  Set aside.
2. Crack the eggs into the large bowl of a stand mixer, or another large bowl if using a hand mixer. Set the bowl over the simmering water you used for the chocolate, whisking constantly until it is just warm to the touch if using a stand mixer.  (Hand Mixer directions:  Beat eggs over the simmering water until hot to touch.)
3. If you are using a stand mixer, immediately place the bowl of warm eggs onto the stand mixer. Using the whisk attachment, whisk the eggs at Medium-High speed until very light colored and “billowy” – it should look like softly whipped cream.  This takes about 5 minutes. (Hand Mixer directions: Beat hot eggs 5 minutes or longer if they are not completely cooled after 5 minutes.)
4. Gently fold half of the egg mixture into the chocolate mixture using a wire whisk or rubber (or silicone) spatula, until few streaks remain.  Then using a rubber (or silicone) spatula, gently fold in the remaining eggs, making sure the heavier chocolate mixture is evenly incorporated and just one or two streaks remain.
5. Pour into prepared pan, which is in the larger (or roasting) pan, and place the roasting pan into the preheated oven.
6. Pour 1 inch of HOT (from your faucet) water into the larger or roasting pan. After 5 minutes, loosely cover with a section of buttered foil. Bake 10 minutes longer. (If using a 9” Springform, check for doneness after 8 minutes.) You want it to still wobble when you move the pan.
7. Remove from the oven, and carefully take the Springform pan out of the hot water bath.  Unwrap it from the foil and set on a wire rack to cool 45 minutes.  After 45 minutes, wrap tightly in plastic wrap and refrigerate at least 3 hours before removing from pan.
8. When ready to remove the cake from the pan, have ready: 1) Your desired serving plate, and 2) a buttered plastic wrap-covered flat bottom from a tart pan or other flat plate.
9. Using warm towels, (or a hair dryer), gently warm the sides of the springform.  Run a knife around the edge between the cake and the side of the pan. Gently loosen the pan sides, then invert onto the buttered flat dish. Then invert again onto your serving plate.  
10. Serve with whipped cream, raspberries or whatever you desire.  I served mine with whipped cream and Ina Garten’s Raspberry Sauce.