Preheat the oven to 180 C/350 F. Sift maida, baking powder, baking soda, salt and cocoa powder. Keep aside. In a bowl beat eggs with pinch of salt until mixture becomes slightly foaming and pale. then slowly add sugar and beat till it is pale yellow and is increased in volume .not whipping the eggs for long will result in dense cake..Add 1/3 of the cake flour mixture and mix with spatula taking care that air does not escape. Then Add melted butter to the batter. Transfer it onto a baking tin greased with butter and lined with parchment paper and bake for 20-25 mins. after the cake is fully baked, when pressed gently down the cake it will bounce back(i.e. the cake is soft) and skewer inserted in the centre comes out clean. cool the cake completely