Ingredients
1. Sorghum flour (1/2 cup)
2. rice flour (1/2 cup)
3. xanthenes gum (1 ½ tbsp)
4. baking soda (1 tsp)
5. dark brown sugar (3/4 cup packed)
6. eggs (3)
7. vanilla extract (2 tsp)
8. tapioca flour (1/2 cup)
9. sifted cocoa powder (1 cup)
10. baking powder (2 ½ tsp)
11. butter (3/4 cup)
12. white sugar (1 cup)
13. eggs yolks (2)
14. buttermilk (1 ½ cup)
15. chocolate chips (5 ounces)
16. vanilla extract (1/2 tsp)
17. sour cream (1/2 cup)
18. heavy cream (1 tbsp)

Method of preparation:-
1. First heat the oven to 350 degrees F or 175 degrees C. Take a pan of 9*13inch, grease it and then keep it aside.

2. Take a bowl of medium size, mix rice flour, tapioca and sorghum flour in it and mix baking soda, baking powder, xanthenes gum and cocoa powder in it.

3. Take a mixing bowl of large size, cream the butter in it until it gets light and fluffy. Gently beat white and brown sugar in it until it gets fluffy. Then beat eggs and egg yolks by one in it and then add vanilla. Add this mixture to the flour mixture; beat it on low speed to form batter. Then pour the batter into the prepared pan.

4. Place the pan in oven and bake it for about 30 to 35 minutes at 350 degrees F until the knife inserted in the center comes out clean. Then keep it to cool.

5. For Icing; take a microwave bowl; melt the chocolate chips in it. Then take out the bowl from oven and keep it to cool slightly and then mix vanilla and sour cream in it. Add heavy cream in it and mix it well. When the cake gets cool then spread the frosting in thin layer on the top.