1. Prepare the sponge CakePlace the rack in the center of the oven. Preheat the oven to 350°F. Butter a 9 x 13-inch baking sheet using 20 ml of butter and line with parchment paper. Fill a saucepan one-third full of water and heat over medium heat until the water is just below boiling. Empty the liquid eggs in a large bowl and place the bowl over the saucepan to create a water bath. Measure 120 ml2P | 160 ml3P of granulated white sugar and mix with the liquid eggs using an electric mixer or a whisk until the mixture is frothy and the sugar is completely dissolved,, about 5 minutes. Remove from heat. Using an electric mixer or whisk, beat the egg mixture for 3 to 5 minutes, or until mixture is thick and ribbon-like. Sift in the spice mixture (the flour, cocoa and baking powder) gradually by folding in the mixture with a spatula without overworking it. Add a pinch of salt. Spread the dough on the baking sheet lined with parchment paper, making sure to even out the surface with a spatula without crushing the mixture. Place the hazelnuts on another baking sheet and toast in the oven along with the sponge cake. Bake the sponge cake for 10 to 12 minutes or until a toothpick inserted in the center comes out clean. Let cool completely for at least 20 minutes.
2. Make the syrup and grind the hazelnutsIn a saucepan, bring 60 ml 2P | 80 ml 3P of water and 60 ml 2P | 80 ml 3P of white sugar to a boil. Using a knife, cut the vanilla bean in half and scrape out the vanilla paste from the inside, then add everything (the pod and its flesh) to the boiling water. Remove from heat and let cool completely. Place the roasted hazelnuts on a cloth, and wrap them. Roll the hazelnuts gently to remove the scales. Remove the cloth and crush the hazelnuts with the back of a saucepan.
3. Prepare the hazelnut creamingIn a large bowl, mix the remaining softened butter with a spatula, 240 ml 2P | 320 ml 3P of powdered sugar and 30 ml 2P | 45 ml 3P of hazelnut praline (save the rest for step 5). Then add 15 ml 2P | 20 ml 3P of milk. Mix with an electric mixer for 1 minute to make the creaming foam. Set aside.
4. Roll the logInvert the sponge cake onto a cloth that’s the same size as the cake or larger and carefully remove the parchment paper. Using a brush, apply a thin layer of vanilla syrup to the cake. Save the remaining syrup for step 6. Using a spatula, apply the hazelnut creaming to the entire sponge cake, keeping an inch with no creaming all around the cake. Top with half of the crushed hazelnuts*. Add the remaining ⅔ of the hazelnut praline to the sponge cake in thin horizontal strips using a pastry bag (or a plastic bag with a hole in it). Gently roll the sponge cake using the cloth, starting from the shorter side, tightening with each movement (refer to the Chef’s class video to get this step right). Place the rolled log** in the refrigerator in its cloth for at least 1 hour.
5. Prepare the whipped creamIn a bowl, whip the cream with 10 ml 2P | 15 ml 3P of powdered sugar with a whisk or electric mixer until you see semi-firm peaks. Add the remaining powdered sugar and a spoonful of vanilla syrup to taste and mix. Refrigerate until ready to serve. You can use the remaining syrup for something else, like a cocktail!
6. Add the final Creaming and toppingsRemove the log from the cloth. Cut the ends of the log, then use a spoon dipped in water to make dumpling-sized whipped cream toppings, and place them on the top of the log. Cover with hazelnut praline coulis and garnish with the remaining hazelnuts. Sift a little powdered sugar on top of the log. Set aside in the refrigerator for a minimum of 2 hours before serving. Enjoy!