The Best Sponge Recipe!

This is my new favourite sponge recipe - the trick? Use duck eggs instead of hen eggs - they are much richer in flavour and wow, you'll be glad you tried them out :) Just be sure to weigh the eggs as they can vary massively in size (and don't seem to have as standard sizes as hen eggs).
If you can't find duck eggs, use hen eggs - the recipe will still work and taste nice (just not quite as heavenly).
I filled my sponges with raspberry jam and covered the cake with a vanilla buttercream. Then to have some fun, I gave painting a go and used concentrated gel food colourings to paint a duck on the top of the cake :D This is obviously optional but worked quite well (given my limited artistic talents).
The cake is delicious and will keep for 3-5 days in an airtight tin :)

Makes one 23cm cake

Ingredients:

For the cake:

• 250g butter, melted
• 250g duck eggs (around 4) or equivalent weight of hen eggs
• 250g golden caster sugar
• 250g self-raising flour
• 1 tsp baking powder 
• 1 tsp vanilla extract

For the buttercream:

• 200g butter, softened
• 400g icing sugar
• 1 tsp vanilla extract
• 1-2 tbsp milk

To finish:

• Raspberry jam (around 150g)
• Food colourings of your choice
• Paintbrushes

Method:

1. Preheat the oven to 180c (160c fan)/ 355f/gas mark 4. Grease and line the base of two loose bottomed (or springform) 23cm round cake tins.

2. Whisk the eggs in a large mixing bowl. Pour in the sugar and keep whisking for 3-5 until the mixture is pale and has at least doubled in volume (you can use an electric whisk at this stage if you like).

3. Whilst whisking, pour in the melted butter and vanilla extract. Once all of the melted butter has been added, sift in the flour and baking powder.

4. Fold the flour into the batter with a large metal spoon, just until you can see no more pockets of flour. As soon as this happens, evenly distribute the cake batter between the two cake tins.

5. Bake for 25-30 minutes, or until the tops of the cakes are golden, they are starting to pull away from the sides of the tin, and a skewer entered into the centre of the cake comes out clean.

6. Leave to cool for 5 minutes in the tin, then turn out onto a wire rack to cool fully.

7. To make the buttercream, beat the butter in a large mixing bowl with a wooden spoon until it is very soft (it will appear like a soft spread). Sift in half of the icing sugar and keep beating to incorporate the icing sugar.

8. Sift the other half of the icing sugar into the bowl, along with the vanilla extract and 1 tablespoon of milk. Beat until all of the icing sugar has been incorporated. If the mixture appears to thick (it is very hard to beat), add a little more milk (a teaspoon at a time). If when you spoon some buttercream out of the bowl, it immediately falls off the spoon, the mixture is too slack - if this happens add a few tablespoons of icing sugar. You want a spoonful of buttercream to slowly fall off the spoon, and to be spreadable.

9. To assemble the cake, level the top of both cakes off with a serrated knife. Any leftover bits are chef's perks, or can be frozen to use another day for cake pops.

10. Spread the jam all over the top of one of the cake layers. Top with about 1/4 of the buttercream, being careful to spread the buttercream evenly over the cake layer.

11. Top with the other layer of cake. Use a palette knife to smooth a very thin layer of buttercream over the top and sides of the cake - this acts as a crumb coat and gives you a better finish.

12. Refrigerate the cake for 10-15 minutes, until the buttercream on the cake no longer sticks to your finger.

13. Take the cake out of the fridge and cover the top and sides with the remainder of the buttercream.

14. To paint the cake, simply use the food colouring gels as paint pots, and go for it :) The food colouring I use is Wilton branded (like these), and it worked really well :D You can use disposable gloves if you're worried about getting the food colouring on your hands, and I used Kitchencraft paintbrushes (like these), but I'm sure any clean artist paintbrushes would work just as well)

15. Enjoy!