Chocolate truffle cake

INGREDIENTS 

For chocolate sponge cake :

All purpose flour/maida : 1 cup
Cocoa powder : 1/3 cup
Baking powder : 1 tea spoon
eggs : 3 (room temperature)
Sugar : 1 cup
Salt : 1/2 tea spoon 
Milk : 1/3 cup 
Oil : 1/4 cup

For sugar syrup :

Sugar : 1/2 cup
Water : 1 1/4 cup