Preheat oven to 350 degrees F. Butter and flour a 9" springform pan.

 

Make the cake: Melt 1 lb of the bittersweet and 2 oz of the unsweetened chocolate over simmering water. Set aside to cool. Cream 8 oz butter, 3/4 cup sugar, egg yolks, and vanilla. Stir in the chocolate and set aside.

 

In an electric mixer, beat the egg whites and salt to stiff peaks. With the machine running, add the remaining 2 Tbsp sugar. Fold in 8 oz sifted flour. Stir 1/3 of the egg whites into the chocolate mixture to lighten it.

 

Fold in the remaining egg whites, gently but thoroughly. Turn into the springform pan. Bake approximately 1 hour.

 

To check for doneness, insert a toothpick gently into the cake. It should come out dry. Remove the ring of the pan and cool the cake on a rack.

 

Make the apricot filling: Purée the apricot jam through a food mill fitted with the finest disk (or use a food processor). Stir in the apricot brandy. Set aside until ready to use.

 

Slice cake in half horizontally to make 2 layers. Spread the bottom layer with two thirds of the apricot filling and top with the second layer.

 

Spread top and sides of the cake with a thin layer of filling. Chill.

 

Make the glaze: Melt 8-10 oz remaining chocolate and remaining 1 oz (2 Tbsp) butter over simmering water. Remove from heat and cool until it reaches glazing consistency. Spread over cake and chill.

 

Remove sachertorte from refrigerator 1 hour before serving.