Preheat the oven to 350º F. Prepare a 9-inch round cake pan by spraying with baking spray or buttering and lightly flouring.
Beat eggs and powdered sugar with an electric beater until frothy.
Sift flour, baking powder, baking soda and cocoa powder. Keep aside.
Add oil gradually to the frothy egg-sugar mixture and keep beating slowly.
Stir in vanilla essence.
Gradually fold in the flour mixture, with an upward and downward movement, using a wooden spoon. Don’t overmix.
Transfer the cake batter to a greased round tin.
Bake at 180 C/350 F for 35-45 minutes.
Test the cake by inserting a clean knife in the centre of the cake. If the knife comes out clean, the cake is ready.
Remove the cake from the tin after 5 minutes.
Meanwhile, boil together the sugar and water for 2 minutes for the sugar syrup. Keep aside.
For the ganache, heat the cream in a heavy bottomed pan over low heat. Do not boil.
Once the cream heats up, add the chocolate chips to it. Stir well to make a smooth, lump-free mixture. Remove from heat and allow to cool.
Beat 200 grams dairy cream till stiff peaks form. Mix about 1 cup of the chocolate ganache to the whipped cream to make the chocolate cream. Keep the remaining ganache for the topping.
Thinly remove the top layer of the cake.
Cut the chocolate sponge cake into 3 layers.
Place the bottom layer on a plate. Lightly pour the cooled sugar syrup.
Then spread about ¼ of the prepared chocolate cream on it.
Then place the second sponge over it and soak with half the sugar syrup using a spoon or brush.
Spread some chocolate cream on it.
Then place the top layer of the cake on it. Soak with the remaining sugar syrup.
Cover the top and sides of the cake with the remaining chocolate cream.
Place the cake in the freezer for 15-20 minutes, till the cream becomes firm.
Remove the cake from the freezer and place on a rack. Place a plate under the rack.
Pour the prepared ganache on the creamed cake and tilt it to cover the sides. You can re-heat the ganache with 2 tbsp. of water, if it becomes too thick. It should be thin enough to flow.
For the curls, peel the side of a chocolate slab at room temperature with a peeler to get curls. If the chocolate is cold, curls will not form. Keep the curls in the fridge
Arrange the chocolate curls on the cake. Decorate with Oreo biscuits.
That's it! Your decadent and beautiful Chocolate truffle cake is ready.