Fatless Sponge

Fatless sponges are most typically used in swiss rolls, or any cake where thin layers are called for. A "normal" cake uses butter to hold the air, while fatless sponges (and genoise, which are a variation) use whisked eggs to generate the structure, then the flour is gently added before baking. They cook very rapidly (and cool as fast, as there is very little bulk), and can be a quick way of whipping something up.

One thing I've found is that because the whipped egg forms the structure, rather than the flour, it's possible to alter the ingredients quite easily without affecting the overall bake. I regularly bake this sponge using a sugar substitute (xylitol) for my lunchtime fruit pots, and when I did this run-through I used gluten-free flour (after a discussion at work where someone with a gluten intolerance was asking advice). You can also make chocolate sponge by substituting about ¼ of the flour with cocoa powder (and omitting the vanilla essence).

It's pretty important to use room temperature eggs for this, cold eggs will not hold as much air. It's also key not to over-beat the eggs (I strongly recommend using a stand mixer for these sponges, as there is a lot of whisking to do!)...if the mixture is too stiff, the final cake will be dry. Finally, this is a really good test of your folding ability...once you're whisked in the air to the eggs, the last thing you want to do is stir it all out again. I have a "lucky spatula" that I use...it's really thin and flexible, and can get to the bottom of my stand-mixer bowl to hunt out any errant pockets of dry flour.

Fatless Sponge - Recipe

Ingredients

• 4 large eggs (room temperature)
• 60g caster sugar
• 100g self-raising flour
• 1 tsp Vanilla Essence

1) Pre-heat the oven to 200'C

2) Prepare a swiss-roll tin. Grease it, and then line it with baking parchment, making sure that it is tightly and neatly into all the corners.

3) Place the eggs, vanilla and sugar in a stand mixer bowl with the whisk attachment

4) Whisk gently until the sugar and eggs have combined, then increase to full speed.

5) You are looking for the "ribbon stage" of the mixture. It will probably take 5-8 minutes to get there. The ribbon stage is the point where, when you pull out the whisk, a visible trail is left on the surface of the mixture (see photo). If there is no visible trail, it's under-mixed, and if a peak forms, it's over-mixed. It's better to check while it is still slightly under-mixed, as you can always keep going for another minute or two

6) Gently sift your flour onto the whipped mixture. This is one of the only times I use a sieve for flour

7) Carefully fold the flour into the egg mixture. Folding is a fine art, and one I find very difficult to explain. I run a thin spatula round the outside of the bowl, then bring the mixture over the top of itself (folding it in), before turning the bowl 90' and repeating. You need to make sure you get right to the bottom of the bowl, and carefully hunt for any pockets of dry mixture. As soon as all the flour is combined, stop mixing.

8) Carefully pour the mixture into the prepared baking tray...again you want to retain as much air as possible.

9) Tilt the tin to move the mixture to all the corners (don't smooth it with a spatula/palette knife, as this will remove the air)

10) Place in the oven for 6-7 minutes. It's done when it is just starting to pull away from the sides of the tin.

11) remove from the oven, and turn upside down onto a sheet of baking parchment.

12) Carefully remove the tin and peel off the baking parchment

13) If you are making a roulade, then you now want to pre-roll the cake, otherwise leave it to cool.

Options

• The sugar can be replaced by a baking-suitable sugar substitute (I use xylitol)
• The flour can be replaced by gluten-free flour. If it's plain flour, mix in 1 level teaspoon of baking powder to the flour BEFORE you add the flour to the egg mixture
• To make a chocolate sponge, swap 25g of the flour for cocoa powder