Cream shortening, 1 1/2 cups sugar and egg yolks until light. Add a
few drops of milk if needed to cream sugar. Add chocolate and blend
thoroughly. Sift flour with baking powder and salt. Add dry
ingredients alternately with milk to chocolate mixture, blending well
after each addition. Stir in vanilla and chopped nuts. Beat 2 egg
whites until frothy. Gradually add remaining 1/2 cup sugar, beating
until whites are stiff. Fold into batter. Turn into 2 greased and
floured 9-inch layer cake pans. Bake at 350F 30 to 40 minutes, or
until cake springs back when lightly touched with finger in center of
cake. Cool slightly then remove layers from pans and cool completely
on wire rack.
To make frosting, combine 3/4 cup sugar and brown sugar in heavy
saucepan. Add hot water and cream of tartar and stir to blend. Cover
pan and slowly bring to simmer. Uncover pan and cook until syrup
spins long thin thread. Remove from heat. Beat 3 egg whites until
stiff. When syrup stops bubbling, pour over beaten whites in thin
stream, beating constantly until fluffy. Use to frost cooled layers.
If desired, melt 1 ounce semisweet chocolate with 1/4 teaspoon butter
and drizzle over frosting. Carefully swirl it over frosting with a
thin spatula to give marbled effect.
