Well, you do not need flour but you need glucose biscuits to make this yum tangy fluffy cake. 

Ingredients – 

1- 4 Cups of powdered glucose biscuits

2- 2 Cups of coco powder(unsweetened)

3- 2 Cups of powdered sugar

4- 6 Tbsps of Tang powder

5- 2 Cups of evaporated milk

6- 1 Cup of clarified butter (desi ghee or unsalted butter) 

7- 1/4 Cup of dry milk powder(unsweetend)

Recipe (Method) – 

1- Mix powdered biscuits and baking soda in a big bowl very well. Now mix in 4 Tbsps of Tang powder in it and mix again. 

2- In a pan take 1 cup of evaporated milk, 1 cup of powdered sugar, 1 cup of coco powder(unsweetened) and 1/2 cup of butter or desi ghee. Mix well and warm the pan. Let the mix boil for 1 minute. Mix well in to the dry mix.

3- Put the batter in microwave safe baking bowl and heat for 3 minutes on high.

4- Take out and cool it. 

5- Now make glaze(ganache) with mixing 1/2 cup butter/desi ghee, 1/4 cup of powdered sugar, 2 tbsps of Tang powder, 1 cup of unsweetened coco powder and 1/4 cup of unsweetened milk dry powder . Boil and mix well. 

6- Spread very well over the cake, glaze the sides with butter knife for sure and cool it before serving.

7- You need to cool it for 2 hour before serving otherwise it will stick to the knife.