Preheat your oven to 180°C (350°F)Prepare your pan. Grease with butter or spray with non-stick spray the base and sides of a 25x38cm (10x15-inch) baking pan /swiss roll pan/jelly roll pan. Line the pan with parchment paper, ensuring the paper overhangs the pan's sides. This will help you later when trying to remove the sponge from the tin. Grease the parchment paper with butter, as this will help with peeling the paper off once the sponge has baked.
Whip the egg yolks & sugar. In the bowl of a stand mixer fitted with the whisk attachment, add the egg yolks and light brown sugar and whip until the mixture is light and creamy, about 4 minutes. When lifting out the whisk, you want to be able to see trails of the mixture for a few seconds.
4 large eggs, 65 g light brown sugar
Add molasses, golden syrup and oil. Add the molasses, golden syrup and vegetable oil into the egg yolks and whip until well combined. Note: scrape down the sides and in particular the base of the bowl a couple of times during this process. Molasses is heavier than the whipped yolks and tends to sink to the bottom of the bowl where it sticks.)
50 g molasses, 50 g golden syrup, 15 g vegetable oil
Sift in dry ingredients. Sift in the flour, ground ginger, baking powder and salt directly onto the egg yolk mixture into the bowl and mix at low speed until just a few flour streaks remain.
100 g plain flour (all-purpose), 2 teaspoon ground ginger, 1 teaspoon baking powder, ¼ fine salt
Whip egg whites. In a separate clean and dry bowl, whisk the egg whites until soft peaks form and then add the white sugar. Continue to whip the egg whites until stiff peaks form and they're firm and glossy.
50 g granulated sugar
Fold egg whites into the egg yolk batter. Add a quarter to the whisked egg whites into the batter and fold through well to loosen the mixture. Add the remaining egg whites and using a large spatular, fold through gently until well combined.
Pour batter into baking pan and bake. Pour the batter into the prepared pan and wiggle/turn the pan to move the batter to the pan's corners. Tap the pan firmly on the work surface a couple of times to release any air bubbles. Use an offset spatular if needed to smooth out the surface. Bake for 10 to 12 minutes until the centre springs back and the sponge is golden.Cool. Once baked, remove the pan from the oven and set the tray on a wire rack for ten minutes (no longer though as the sponge still needs to be warm when it gets rolled later on.) Prepare your tea towel. Whilst the sponge is resting, lay a tea towel or piece of parchment paper on your work surface and dust lightly with powdered icing sugar. (Alternatively, sprinkle with caster sugar.)Invert the sponge onto the tea towel. After ten minutes of the sponge being out of the oven, run a knife around the edge of the pan and invert the sponge onto the prepared tea towel whilst it is still warm. Peel off the parchment paper and roll. Gently peel off the parchment paper on the bottom of the sponge. Roll sponge up. Starting from the sponge's short end, using your hands, roll the sponge up gently but firmly until it is totally rolled into the tea towel (or parchment paper). Set the roll aside with its seam side down to cool completely.