Preheat the oven to 350 degrees. Prepare a 9” tube cake pan by greasing lightly and lining the bottom with paper. Combine the egg white and dash of salt in a small bowl; beat until foamy. Add ¼ cup sugar, a little at a time, beating at high speed of electric mixer until stiff peaks form. Blend in 2 tablespoons flour and the coconut.
Melt the chocolate in ¼ cup water over very low heat, stirring until blended; cool completely. Meanwhile, measure sifted flour, baking soda, salt, and baking powder; sift together. Cream the butter and 1 cup of the sugar; add the eggs, 1 at a time, beating well after each addition. Blend in the vanilla. Combine the sour cream and the cooled chocolate, blending well; add to the butter mixture alternately with the flour mixture, mixing well after each addition.
Pour about 2 cups of the cake batter into the tube pan. Sprinkle with ½ cup of the coconut mixture. Top with another 2 cups batter and ½ coconut mixture; then with the remaining batter and coconut mixture. Bake for 50 to 55 minutes. Cool in the pan on a cake rack for 15 minutes and then remove the sides of the pan, leaving the tube in the cake. Finish cooling cake on the rack before removing the tube. Spread with chocolate glaze and top with more coconut, if desired.
Source: “Better Homes and Gardens New Cookbook”, Meredith Publishing Company, 1965