1. Heat oven to 300 degrees. Butter and sugar an 8-inch springform pan, and set aside.

2. Chop chocolate into small pieces, and place in a double boiler or heatproof bowl with the butter. Place over a pan of barely simmering water, and stir occasionally until completely melted. Remove from heat, and set aside.

3. Place 3 yolks, whole egg, salt, and 2/3 cup sugar in the bowl of an electric mixer fitted with the whisk attachment. Beat on medium high until thick and pale yellow, about 5 minutes. Transfer to a medium bowl.

4. Wash mixer bowl and whisk; add the 6 egg whites and 1/3 cup sugar to the clean bowl. Whisk until mixture is stiff and shiny, about 4 minutes.

5. Pour chocolate mixture into the egg-yolk mixture, and fold together. Gently fold in egg-white mixture until just combined. Pour into prepared pan, and bake until cake has risen quite high and top has begun to crack, about 1 hour 10 minutes. The center of cake should be set but not at all dry. Allow to cool completely on rack, then remove sides of pan.

6. Cut each cherry in half by running the tip of a paring knife around each, starting at the stem. Gently twist cherries to separate halves, and carefully remove pits. Place cherries and remaining 2 tablespoons sugar in medium skillet set over medium heat. Cook until sugar is dissolved and cherries release their juice, about 5 minutes. Remove pan from heat, add kirsch, and transfer carefully back to heat. Allow to cook until liquid is slightly thickened, about 2 minutes.

7. In a medium bowl, whip cream to soft peaks. Serve chocolate cake with warm cherry mixture and a dollop of whipped cream.