Kitchen Sponge

It was a banner weekend chez Fractured Amy, since Sir finally returned from Tokyo just in time to celebrate his birthday. A cake was required for the festivities and the birthday boy, as per tradition, was given free choice. A flourless chocolate cake, perhaps? Maybe a dacquoise or a meringue? Something gluten-free, of course.

Imagine my palpitations when the man-of-the-house insisted that only a humble jam sponge would do.

I need to parse this request for Colonial readers. A sponge is a simple English cake made with butter, sugar, eggs, and flour - and not much else: the texture is hard to describe, as its equivalent is unknown on this side of the Atlantic. The flavour and color are similar to poundcake, but it has an airier texture and a coarser crumb. A good sponge is very light and melty. As long as it's refrigerated, it has excellent keeping abilities - and can even be frozen with no ill effects. Sponges are traditionally served at tea time, split and filled with jam and/or cream and dusted with powdered sugar. They are, as the saying goes, top-ho.

And, needless to say, full of gluten. I have not baked a proper sponge since gluten-freedom was imposed from above over a month ago.

Never one to be deterred by such concerns, I set to work with a will. I have always used a classic all-in-one sponge recipe that was given to me when I was first married by a friend who felt my English husband would not be satisfied otherwise. In adapting the recipe, I considered some lessons gleaned from my madeleine experiments. First, a small amount of xanthan gum would be required, although far less than the usually-recommended 1/2 tsp. per cup of flour, which causes a dreadful metallic aftertaste and molar-coating sliminess. Second, the recipe would need either more moisture or less flour, to avoid the corn-bread texture problem that perennially plagues the user of g/f flour - or plagues me, anyway.

I was astonished to get it right after only three cakes. The first was quite reasonable but had a slightly heavy texture and did not rise properly in the middle. I attributed this to a deficit of baking powder and a lack of moisture. I remedied the situation by adding an additional half teaspoon of baking powder and 3 tablespoons of water to the second batch of sponge batter. While I was thrilled with the result (an evenly-risen, light and airy sponge), Sir was convinced he could taste the excess baking powder.  Dismayed, I glared at the baking powder tin accusingly, only to discover the contents were well past their best-by date. 

The final perfect cake was produced with fresh baking powder (the original amount) and extra water.  The result was very, very delicious, and gobbled up happily by all concerned.

It must be recorded, in the interest of full disclosure, that when Sir sliced himself a second (or was it a third?) piece of cake, he accidentally did so from the sponge with extra baking powder, and did not notice the difference.

Classic All-in-One Gluten-Free Sponge

• 4 oz. gluten-free all-purpose baking flour
• 2.5 teaspoons very fresh baking powder (otherwise 3 tsp.)
• scant 1/8 tsp. xanthan gum
• 4 oz. sugar
• 4 oz. butter, softened at room temperature
• 2 large eggs
• 2-3 drops vanilla extract
• a few tablespoons of warm water

Preheat the oven to 325 deg F and butter an 8-inch round cake pan. Line with parchment/silicon paper and butter that, too.

Sift the flour, baking powder, xanthan gum and sugar several times into a reasonably large mixing bowl. Cream the butter a bit to soften, then add it and the eggs to the dry mix, beating with your best electric handmixer until it's creamy. The final compound should drop with a spludge when you tap a wooden-spoonful of it onto the side of the bowl: I find with g/f flour, you need to add a full 2 or 3 tblsp. of warm water to get the consistency right. It will not be a thin batter like many American cakes: it is a thick mixture the consistency of, say, creamy smooth mashed potatoes.

Glop the batter into the prepared pan - you will need a spatula for this. Spread the mixture right to the edges of the pan and flatten out any obvious molehills.

Bake for 30 minutes or until it's done. Upon removing it from the oven, let it cool ever-so-briefly, then flip it onto a cake rack and remove the paper so to the sponge can cool completely. You can split it and fill with whatever you like or bake two and pile one on t'other with deliciousness in between. Sir likes strawberry jam and buttercream; I am a lemon curd/whipped cream sort of girl. You can keep any leftover cake in the fridge.

NB A wonderful gluten-filled sponge may be produced by substituting 4 oz. self-raising flour for the g/f flour, baking powder and xanthan gum. In that case, you will probably not need to add additional water. The method is identical.

The sponge, cross-sectioned: note the even rising and light texture,
achieved with just the merest hint of xanthan gum.
It was sandwiched as per Sir's request 
with strawberry jam and custard buttercream.

Next up: I reveal my super-secret recipes for lemon curd and buttercream, without which no sponge is complete.