Preheat oven 200°C. Grease and line a 26cm x 40cm x 2.5cm tray.
Separate the egg whites and yolks. Whip the egg whites, adding caster sugar and salt, slowing turning into stiff peaks.
Whip the egg yolks until they change to light yellow in colour. Add in the buttermilk, olive oil and vanilla essence.
Using a spatula, gently fold the sifted flour and Gingerbread Spice through the egg yolk mix.
Add a small amount of egg whites into the Gingerbread Spice mixture. Then, in two more parts, gently add the rest of the egg whites until the batter is smooth and airy.
Pour the batter into the prepared tray. Tap the tray to break any air bubbles. Bake in the oven for 25-30 minutes until golden brown.
Place a sheet of baking paper (larger than the cake) or a thin tea towel flat on the benchtop. Once the cake comes out of the oven, quickly run a knife around the edges of the tray to loosen the cake and immediately turn onto the baking paper or tea 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 baking paper or tea towel. Do this slowly and gently. The cake will be warm. Allow the cake to cool completely rolled up.
To make filling, whip the cream to form soft peaks. While whipping, add in the sifted icing sugar and Rose Petal Powder. Unroll the cake and spoon the filling over, spreading it right to the edges. Carefully re-roll the cake to form a shape of a log.