How To make Mt. Airy Chocolate Souffle Cake

1 lb Semisweet chocolate
1 c Butter
6 tb Brandy
9 Eggs; separated
1 c Sugar, plus 1/4 c
1 ts Salt
1 ts Cream of tartar
1 tb Vanilla
Butter the springform pan. Line the bottom with parchment paper. Cut a strip of parchment paper about 30x5 inches and line the sides of the pan forming a collar. Melt the chocolate and butter in the top of a double boiler. Add brandy off heat. Beat the egg yolks until very light and lemon colored. Gradually beat in the 1 cup sugar. Fold into the chocolate mixture. Beat the egg whites with the 1/4 cup sugar, salt, and cream of tartar until stiff peaks form. Fold all together with the vanilla extract. Pour into the prepared springform pan. Bake in an oven preheated to 350 for 55 minutes, until the center is just set. Let cool on a rack 20 minutes. Remove the pan's walls and the paper collar. Continue to cool at room temperature; cut into 12 pieces with a knife blade dipped in warm water. Serve at room temperature with cold Soured Cream (see recipe). SOURCE: Biscuits, Spoonbread, and Sweet Potato Pie (pg. 307) -----