(Nutrition information is calculated using an ingredient database and should be considered an estimate.)
Preheat the oven to 180°C. Butter a Swiss roll tin with vegan spread, then line the tin with baking paper and butter the top of the paper. This will ensure an easy release later! Make sure the baking paper rises an extra cm above all sides of the tin.
Make the cake: Using a hand mixer or a stand mixer fitted with the whisk attachment, beat the Aquafaba, cream of tartar and 1/3 cup granulated sugar together in a medium bowl on high speed for 5 minutes or until stiff peaks form. Set aside. In another bowl, beat the egg replacer, water, remaining sugar, and vanilla together until creamy, about 2 minutes.
Sift the flour, 3 tablespoons of cocoa powder, baking powder, and salt together in a large bowl. Pour the melted spread and egg replacer mixture over the dry ingredients. Beat everything together on medium speed until completely combined. Using a rubber spatula or wooden spoon, gently fold in the Aquafaba whites until completely combined. Avoid over-mixing and deflating the Aquafaba whites. The batter will be very light.
Spread batter evenly onto the prepared tin. It will be a very thin layer. Shimmy the tin on the counter to smooth out the top. Bake for 10 minutes or until the top of the cake gently springs back when touched with your finger. Do NOT over-bake.
Prepare to roll: As the cake bakes, place a thin tea towel flat on the counter. Using a fine mesh sieve, dust the towel with 2 tablespoons of cocoa powder. Once the cake comes out of the oven, quickly run a knife around the edges to loosen it. Immediately invert it onto the towel. Peel off the baking paper that was on the bottom of the cake as it baked. Starting with the narrow end, begin tightly rolling the hot cake up with the towel. Do this slowly and gently. The cake will be warm. Allow the cake to cool completely rolled up in the towel. Place it in the fridge to speed it up, about 3 hours.
Bring the cake to room temperature if it was in the fridge. The cake is prone to cracking if unrolled while it's cold.
Using a hand mixer or a stand mixer fitted with a whisk attachment, whip the Flora Thickened Plant Cream, sugar, and vanilla extract on medium-high speed until stiff peaks form, about 2-3 minutes.
Slowly and gently unroll the cake. Spread the whipped Flora Thickened Plant Cream evenly on top, leaving about a 1cm border around the cake. Gently roll the cake back up, without the towel this time. Place on a wire rack set on a baking sheet to catch the extra ganache. Set aside on the counter or in the fridge as you prepare the ganache.
Make the ganache topping: Place chopped chocolate in a medium heat-proof bowl. Heat the Flora Thickened Plant Cream in a small saucepan until it begins to gently simmer. Do not let it come to a rapid boil. Pour the Plant Cream over the chocolate and let it sit for 2-3 minutes to gently soften the chocolate. Slowly stir until completely combined and the chocolate has melted.
Pour ganache all over the cake roll. Refrigerate for at least 30-60 minutes before slicing and serving.
Remove from the fridge and dust the roll with icing sugar, slice and serve.