Yes, I Will Have No Scrambled Eggs With My Sponge

Having produced an excellent gluten-free all-in-one-sponge, fillings must now be considered. The plain vanilla sponge has many admirable qualities, but it is, as Bill Bryson would say, only 'cautiously flavorful'. It's all about butter and texture - and acting as a foil for the awesome things you layer inside. The most basic fillings are jam and whipped cream, but for company I like to tart things up a bit with lemon curd and buttercream.

Lemon Curd

Home-made lemon curd is tart and zingy, smooth and silky and very, very simple to make. I've been given many recipes over the years, all exactly the same (maybe there is only one recipe in the whole world!). Everybody loves it, even kids. And it is so veddy, veddy English. Imagine you are lazing by the Cherwell on a fine June day, watching the punts gliding by ...

You can substitute any kind of citrus for the lemon, of course, but I like to stick with the classics.

• 1 large lemon: de-zested and juiced
• 2 large egg yolks
• 3 oz. sugar
• 2 oz. room temperature butter, cut into bits

In a bowl, whisk together the lemon juice and the eggs. Combine the lemon zest and the sugar in another bowl that will fit atop a saucepan of simmering water like a double boiler. Actually, it is a double boiler. Pour the juice/egg mixture over the sugar and mix it up, then add the butter bits. Stir over the simmering water (heat on low) until the mixture is beautifully thick and and glossy - it can take a while, so be patient. Do not be tempted to turn the heat up, or you will get lemon-flavored scrambled eggs. You will eventually be able to draw your stirring utensil across the bottom of the bowl and make a clean channel for a few seconds. It can take 15 minutes or so.

Remove from the heat, decant to a different bowl, and cool before using: it will continue to thicken in the fridge. If you see some coagulated strands of egg white (it happens to the best of us), you can strain them out through a fine-meshed sieve or cheesecloth before the curd cools completely, and nobody will ever know.


Julia Child's Creme au Beurre, a L'Anglaise

There are a bazillion recipes for buttercream out there, but this is the one I use almost exclusively. It's rich and velvety and most importantly, in my opinion, not too sweet. An excellent complement for jam or lemon curd, and totally completely amazing in French macarons. But that is a whole 'nother story.

• 1/3 cup granulated sugar
• 2 egg yolks
• 1/4 cup hot milk
• 4 oz. butter at room temperature (maybe a little more: have some extra standing by)
• optional flavoring (1 tablespoon is sufficient): melted chocolate, vanilla, orange liqueur, coffee, etc.

In a bowl, gradually beat the sugar into the egg yolks with your electric mixer. Keep at it until the mixture is pale and very thick, doing the ribbon thing. Beat in the hot milk very gradually (don't cook the eggs!).

When that's done, transfer the whole lot into a saucepan and apply medium heat while stirring constantly with your beloved wooden spoon. You are now making custard. The mixture will thicken so that it will coat the back of your spoon at around 165 deg F. Don't turn your heat too high or you will get scrambled eggs - are we detecting a theme, here? I use the medium gas setting until it gets quite warm, then turn it down to low while it thickens. Keep stirring!

When you have custardization, remove the pan from the heat and pour the contents into a cool bowl. Julia says the bowl should be sitting on ice, and who are we to disagree? Beat the custard with your electric mixer until it's room temperature. Then, add the butter bit by bit, beating prestissimo all the while, until it's all incorporated and your buttercream is smooth and creamy and luxurious.

NB I do not use a standmixer for this! I find that it is insufficiently vigorous and doesn't keep the entire mixture in constant motion as needs require: even using my electric handmixer, I get a bit tired during this stage. Don't ask me how they did this before electricity - a galley slave with a whisk and tennis elbow, I suppose.

If the mixture starts to curdle, don't panic - that's what the extra butter is for. Keep beating in butter bits until you have liftoff, then (to mix a metaphor) add any optional flavour that floats your boat. The buttercream might need to be refrigerated for a bit until it's thick enough to spread. If you have any left over, it freezes beautifully. It is horrifyingly delicious straight from the bowl.