Ingredients:
350 gm glucose biscuits
1/2 cup drinking chocolate
1/4 cup icing sugar
1/8 cup Coca powder
1/2 tsp vanilla essence
1/2 cup butter (unsalted
1 cup milk
6" x 5" (approx) tray to make the cake
7" x 6" sheet of butter paper

Method:

1-Make fine crumbs of 2-3 biscuits in a mixie keep aside. 
2-Sieve together the dry powder ingredients twice. 
3-Beat butter till soft in a bowl. Add sieved mix spoon by spoon to butter and mix well. 
4-Beat again till shiny and light. Add essence and mix well. Keep aside. Take milk in a shallow plate. 5-Spread the butter paper sheet in the tray. Sprinkle a little of the crumbs all over it. 
6-Take six biscuits. Dip one by one in the milk for a few second and place on sheet side by side. 
7-They should form a rectangle. 
8-Spread a layer of chocolate mixture carefully over the biscuits with a knife. Sprinkle some crubs over it. 
9-Repeat the biscuit, coco, crumbs layers till all the biscuits are used up.
10-Cover the cake on top and sides with remaining. 
11-Decorate with either white or chocolate icing as for sponge cakes and glace cherries or strawberries, you may even use chocolate nuggets, etc. 
12-Chill for 2 hour before serving in the fridge.