Sieve the flour, cocoa powder, Cornflour, salt together. Keep aside.
Remove 1 tbsp out of the sugar and keep aside too. Whisk the eggs, yolks, sugar and vanilla extract together until it is pasty and falls back like ribbon.
Now whisk the egg whites with the 1 tbsp of sugar, till it reaches firm peaks. Mix this into the flour mix.
Add the flour mix in 2 parts into the egg mixture, fold it in.
Pour this into a rectangular tin (43 cm × 30 cm) lined with butter paper. Bake this for 6-7 minutes in a preheated oven at 220 degree Celsius. Sprinkle icing sugar on the sponge after it is removed immediately.
Invert it on another sheet of butter paper and remove the bottom lining. Roll the sponge cake along with the paper and cover it with a foil, leave it to cool.
Now for the whipped cream filling, whisk all the ingredients mentioned under the "whipped cream" to a desired consistency.
Chill it enough. Spread it on the cooled sponge and carefully roll it. Now cut about 3 inches from end and make a small diagonal cut on the smaller piece. Keep aside. This is for the protruding part from the log.
For the ganache frosting, chop the chocolates, put them in a bowl along with the butter cubes.
Heat the cream and once it starts bubbling from the sides, pour this into the chocolate mixture.
Let it sit for 5 minutes and then mix well. Keep it aside for 4-5 hours so that it hardens enough.
Mix and use the ganache frosting to cover the log. Attach the smaller part of the cake to the main log or swiss roll . Cover this as well to form the the yule log. Decorate it accordingly. Chill and serve.