In a bowl, whisk the egg yolks with 50g of sugar until you obtain a homogeneous and slightly frothy mixture. Incorporate the oil, milk, and vanilla extract in a stream while continuing to mix.
Add the sifted flour and cornstarch. Mix gently until you achieve a smooth and lump-free batter.
Whip the egg whites until stiff with 50g sugar, until you obtain a shiny and stable meringue.
Using a spatula, gently fold the whipped egg whites into the yolk mixture. Perform a folding motion to preserve the aeration of the mixture and avoid crushing the air bubbles.
Divide the mixture into two equal parts. Add a red food coloring to one of the two parts to achieve a bright and uniform hue.
Line a baking sheet with parchment paper. Fill two piping bags with the red and white mixtures.
Starting from a corner of the baking sheet, alternate the red and white mixtures by drawing parallel lines to create a visual effect reminiscent of a candy cane. Repeat the operation over the entire surface of the sheet, ensuring to evenly distribute the batter.
Bake the biscuit
As soon as it comes out of the oven, turn the biscuit onto a damp cloth previously spread out. Gently roll the biscuit in the cloth to give it a cylindrical shape, tightening slightly to avoid cracks. Allow to cool in this shape to set.
Gently unroll the cooled biscuit. Spread an even layer of filling of choice, such as strawberry jam and vanilla cream. Roll the biscuit again, tightening slightly to obtain a well-compacted yule log.