1. Grease and flour a 9-inch by 13-inch by 2-inch baking pan.
2. Preheat oven to 350 degree F.
3. In a large mixing bowl, combine sugar, cocoa powder, and butter. Beat well.
4. Drop eggs, one at a time, and beat after each addition.
5. Add vanilla and self-rising flour in bowl. Mix to combine.
6. Throw flaked coconut and chopped pecans. Fold to evenly distribute.
7. Into the baking pan, transfer the mixture. Spread evenly. Pop the pan in oven and bake for 40 minutes, or until a toothpick when inserted in the center comes out clean.
8. Remove pan from oven and spread marshmallow crème over hot cake. Let the cake cool in pan.
9. For frosting, in a separate mixing bowl, add butter, milk, confectioner's sugar, vanilla, and cocoa powder. Beat until smooth. Cover the bowl with plastic wrap and pop it in refrigerator until cake cools.
10. Spread frosting evenly on cooled cake. This frosting sets slowly, you can cover the frosted cake with plastic wrap and place it in refrigerator for 4 hours or overnight.
11. Cut into slices and serve cake immediately.
If you do not have self rising flour, then for each cup of all purpose flour add ½ teaspoon of baking powder and ½ teaspoon of salt.
You can reduce the cooling time by place the cake in refrigerator for 1 ½ hour and then for ½ an hour in freezer.