Makes 16 sizeable jaffa cakes
For the jelly
2 sheets of leaf gelatine
25g caster sugar
100g good dark chocolate, roughly 70% cocoa solids
For the cakes
2 medium eggs
50g caster sugar
50g plain flour
½tsp baking powder
Butter, for greasing
First, make the jelly. Get started by taking the leaf gelatine and placing it in a bowl with cold water – this will soften it. Line a baking tin or dish with plastic wrap.
Finely grate the zest of two of your oranges and set this aside. Juice all six oranges and pour this juice into a small pan with the sugar. Place over a medium heat until the sugar has dissolved and the juice is hot to touch. It should not boil or simmer.
Once it is hot, add the zest and gelatine and stir until the gelatine has dissolved. If it does not dissolve, return the pan to the heat until it does, stirring gently all the time.
Pour the jelly into your plastic wrap-lined ‘mould’ and leave it to cool. Pop it in the fridge as soon as possible, or the freezer if you’re in a rush. Keep it flat and check it regularly. It should set firm in a few hours.
Make the sponge. Start by preheating your oven to 180°C. Grease 20 holes in two 12-hole cupcake trays with a little butter, to be safe.
Break your eggs into a mixing bowl and add the sugar. Whisk on high using an electric whisk until the mixture almost resembles meringue – it should increase in size by six times, if not more, and be thick and creamy. This might take more than five minutes. Do not attempt to do it by hand.
Sieve in your flour and your baking powder. Use a large metal spoon to gently fold this into your egg mixture. Try not to knock out any of the air you’ve spent ages creating, but the mixture should be smooth.
Spoon the cake mixture into your tins, making sure they are no more than one-third to half full.
Bake in the oven for 7-10 minutes only – you want them on the pale side to maintain softness, and you don’t have the oven set very hot so they shouldn’t dome. Remove from the oven and leave your cakes to cool, then remove them from the tins.
Remove your jelly from the fridge and, if set, you can cut out circles using a biscuit cutter or the top of a shot glass. Make sure the circles are smaller than the tops of your cakes.
Slice off any domes that have risen on the top of your jaffa cakes, then spread on a very thin layer of marmalade (minus any shreds). Stick your jelly circles onto the sponges.
Melt four-fifths of your chocolate – I use a microwave, but you could use a heatproof bowl suspended over a pan of barely simmering water. Whichever way, do it very gently. Finely chop the remaining chocolate. When most of the chocolate has melted, remove it from the heat and add in the rest. Stir until it’s melted.
Holding by the sides, dip your jaffa cakes upside down into the melted chocolate. Let any excess chocolate drain back in and then place each cake on a wire rack, the right way up, to set. After a few minutes, when the chocolate is half set, use a fork to make a criss-cross pattern on the top of your cakes. These will keep for a day or two only, but they won’t last that long.