For the sponge:
For the jam:
Preheat the oven to 360°F.
Oil an oven tray and cover with a baking sheet. Sprinkle oil over the sheet once more and set aside.
Sprinkle some powdered sugar on a kitchen cloth in a 4 x 6-inch rectangle. Set aside.
In a small bowl, mix the almond milk and vinegar, set aside so it curdles for a few minutes, and then add flaxseed flour. In a large bowl, mix the flour, sugar, cornstarch, baking powder, xanthan gum, baking soda and salt. Make a hole in the middle and pour the oil, vanilla extract and almond milk mixture. Beat for 10 seconds.
Put the dough to an oven tray with a baking sheet and smooth the surface. Bake for 12 to 13 minutes or until you can insert a toothpick and it comes out clean.
Allow to cool for 3 minutes and then flip over the prepared kitchen cloth. Remove the paper and fold the rest of the cloth over the edge of the cake and roll carefully. Tuck the edges underneath and allow to cool.
For the mousse, blend all the ingredients except for the chocolate until obtaining a homogeneous paste. Melt the chocolate in a bain-marie and blend with the rest of the ingredients in a blender until smooth. Put in a bowl and allow to cool for at least 30 minutes at room temperature.
For the jam, put the raspberries and sugar on a small pot over medium heat until it boils and cook for 10 minutes, then allow to cool.
Unroll carefully, trying not to flatten the sponge completely. Spread the chocolate mousse and raspberry jam over it. Roll again and leave the seam downwards in a serving dish, placing it on the flat side of the previous roll.
For the mocha cream, put the butter, cream and sifted powdered sugar in a bowl. With a hand mixer, beat until the cream is soft and smooth, this will take about 8 minutes. Then add the rest of the ingredients and beat for about 3 more minutes.
To assemble, cut both ends diagonally and arrange the cut pieces as branches. Cover with butter and mocha cream Use a fork along the log to draw the texture and cut the branches so it looks like tree bark. Decorate with some sliced almonds and raspberries.