This recipe is from a 1977 General Mills insert in Ladies Home Journal magazine.
1 pkg (2 layer size) yellow cake mix
1 pkg (4 serving size) vanilla instant pudding and pie filling mix
1 pkg (4 oz) German sweet chocolate, melted
1 1/4 cups buttermilk*
1/4 cup oil
*Or use 1/2 cup sour cream and 3/4 cup water
Combine all ingredients in a large mixing bowl. Blend, using an electric mixer. Beat 4 minutes at medium speed. Pour into two or three greased and floured 9-inch layer cake pans. Bake at 350 degrees for 25 to 30 minutes or until cake springs back when lightly pressed. Cool in pans for 15 minutes. Remove and finish cooling on wire racks. Fill with coconut filling.
Coconut Filling: Combine 1 cup evaporated milk, 1 cup sugar, 3 egg yolks, slightly beaten, 1/2 cup butter or margarine, and 1 teaspoon of vanilla in a saucepan. Cook and stir over medium heat until thickened, about 12 minutes. Remove from heat. Add 1 1/3 cups flaked coconut and 1 cup chopped pecans. Cool, beating occasionally, until of spreading consistency. Makes 2 1/2 cups. Use to fill between layers and on the top.