Soft Chocolate Cake

Ingredients:
All purpose flour or maida - 1 cup
Milk - 1 cup
Sugar - 3/4 cup
Cocoa powder - 1/3 cup
Oil - 1/4 cup
Baking powder - 1/2 tsp
Baking soda - 1/4 tsp
Lemon juice - 1/2 tsp
Vanilla essence - 1/2 tsp
Salt - 1/8 tsp

For frosting :
Dark chocolate - 150 g
milk - 100 ml
Butter - 1/2 tsp