Firstly in a mixing bowl take powdered sugar and oil whisk it thoroughly add egg and vanilla essence whisk it again,melt dark chocolate in double boiling method aftr it cools down just refrigerate it for jus five minutes take out keep aside

Now to this wet ingredients add dry ingredients all-purpose flour, cocoa powder, baking powder gently fold it with wet ingredients

Now pour half of the batter in to greased tin,put generously melted(semi solid)dark chocolate in the middle again cover it with cake batter, bake the cake for 15-20 minutes at 175 degree centigrade, check whether cake is done,with a tooth pick inserting it in the edge of the cake..