I was making this roulade when some friends from Scotland arrived on our doorstep. Consequently I wasn't paying too much attention to the sponge as I was rolling it up & only realised when I was taking photos that I had rolled it the wrong way.

Ingredients

140 g Potato starch*

110 g Caster sugar

5 Eggs (700 g/dozen)#

1 tsp Cream of tartar

1/2 tsp Bicarb of soda

2 tsp Vanilla extract

extra caster sugar

Filling

Cream

Strawberry jam

or

whatever you want to put in it

* For more information on making sponges & the use of different starches refer to Sponge Basics. This sponge recipe uses the ratio for light sponges it will sink when it comes out of the oven. 

# If using home grown eggs pick 5 medium sized eggs. 

Method

If you keep your eggs in the fridge 1/2 fill the kitchen sink with hot tap water. Put the eggs in the hot tap water for 10 mins. If you keep your eggs at room temperature warm the eggs up by placing them in a dish of warm water (slightly hotter than 37 C).

Turn oven on to 175 C.

Line a large rectangular pan with baking paper. Make sure the baking paper overhangs the edges. I use one of my roasting dishes 32 cm x 25 cm. I have also used one that is 38 cm x 30. Using a larger pan will make a thinner sponge (& more filling will be needed :) ). 

Sift together the starch, cream of tartar & bicarb three times into a mixing bowl. 

The yolks & whites will be whisked/beaten separately; you will need two mixing bowls. If you have two bowls for your stand mixer use those. If you have one beat the yolks first in the mixing bowl, transfer it to the bowl containing the sifted starch & then wash the mixing bowl for whisking the whites.

Measure out 70 g of sugar into the mixing bowl for the yolks. Put the remaining sugar into the bowl/container (not plastic) for the whites. 

Separate 4 of the eggs. Put the yolks in with the 70 g of sugar & the whites in with the 40 g of sugar.

Put the last whole egg in with the yolks & sugar. If using vanilla extract add it to the yolk mix. 

Beat the egg yolks & sugar for ~9 mins until the ribbon stage has been reached. Below are photos of the yolk mix prior to beating & when it has reached the ribbon stage.      

While the yolks are beating stir the egg white & sugar mix to help dissolve the sugar. I usually rest this mixing bowl on top of the hot tap water to help the sugar dissolve. 

If using the same mixing bowl to whisk the egg whites as the one used for the yolks, transfer the yolk mix to the mixing bowl containing the sifted starch. Wash & dry the mixing bowl before putting in the egg whites & sugar mix.  

Whisk the egg whites & sugar for 1 1/2 - 2 mins until stiff peaks form. The length of time to whisk the whites will depend on your mixer & the speed you are using. 2 mins at max speed in my KitchenAid is too long. It is not a disaster if the egg whites are slightly over whipped it just takes a little longer to fold into the yolk mix. 

Fold in the sifted starch mix to the yolk mix. To fold put a spatula/scrapper into the centre of the bowl & push it down through the mix until it reaches the bottom of the bowl. Bring the spatula toward you all the time scrapping the bottom of the bowl. When the spatula is at the edge of the bowl bring it up out of the mix & with a twist of your hand (90 - 180 degree clockwise turn if right handed) turn the spatula over. The mix that was on top of the spatula will now fall back into the middle of the mix. Rotate the bowl clockwise with your left hand while repeating the spatula movement. Ensure the mix has a uniform consistency before proceeding.  

Fold in the whisked whites to the yolk mixture using the technique described above. I usually fold it in without "loosening" the yolk mixture. "Loosening" the yolk mixture should make it easier to fold in the remaining whisked whites. The yolk mix can be "loosened" by adding up to 1/4 of the whisked whites & folding this in. The remainder of the whisked egg whites are then added & folded in.

Pour the sponge batter into the baking pan. Use a spatula to level the top of the batter.

Put the baking pan in the oven & bake at 175 C for approximately 12 mins.  

Bring out of the oven & allow to cool briefly. The sponge should be rolled when it is still warm. 

Cut another piece of baking paper and sprinkle it with the extra caster sugar.

Lift out the cake by using the baking paper.

Invert the cake, gently laying the sponge on the baking paper sprinkled with caster sugar.

Gently peel off the bottom baking paper (now on top).

Put another piece of baking paper on the top.

Starting from the side closest to you, roll up the sponge.

Dampen a teatowel & wrap it around the roll. Allow to cool completely.

Whip some cream & get the strawberry jam ready (or another delicious filling).

Unroll the roulade, take off the top piece of baking paper & spread the strawberry jam on top.

Top the strawberry jam with the whipped cream.

Roll the sponge back up.

Slice, serve & enjoy.