I attempted to make Mary Berry's Jaffa Cakes today. I had to do some converting to make it work in the U.S. system. Here is the recipe I came up with. Sorry about the mix of Metric and Imperial measurements, I was working quickly. I won't apologize for the lack of cup measurements as baking by weight is far more accurate anyway.
For the jello
170g packet of orange Jello
8oz boiling water
1 medium orange - zest only
For the sponge
Butter flavored Pam
1 extra large egg
25g plain flour
1g baking powder
for the topping
8 oz semi-sweet chocolate.
If you can find them, I suggest using the Ghirardelli dark chocolate melting wafers as they melt in the microwave and also cool more quickly for spreading purposes.
You will also need a 13x9 pan, a 12 count muffin pan and a round cookie cutter. Mine was 2 1/4 inches I think though a 2 inch one might have been easier.
1. For the jello. Mix the orange zest and the packet of Jello powder together. Pour in 8oz of boiling water and whisk together. Pour into a 13x9 pan and put in the fridge to set. Some oil in the pan will aid easy removal later.
2. Preheat the oven to 350F and liberally spray a 12 hole shallow muffin pan with Butter Pam
3. For the sponge, whisk the egg and sugar together for 4-5 minutes until pale and fluffy - it will increase in volume. This is such a small amount of cake batter I used a hand held electric wire beater. I was worried my kitchen aid would not cope with so little batter.Sift the plain flour and the baking powder into the batter and fold in until fully combined.
4. Fill each well in the muffin pan with approximately 2 1/2 teaspoons of batter and smooth the top. Bake for 7-9 minutes until the tops spring back lightly when pressed. Leave to cool in the tray for a few minutes then finish cooling on a wire rack.
5. Break the chocolate into pieces then melt in a double boiler. Remove from the heat and LET COOL for quite a while.
6. Using your cookie cutter, cut out 12 disks from the orange jello and place one on top of each sponge.
7. When the chocolate has cooled enough, spoon it over the jello disks so that the tops of the Jaffa Cake are completely covered. Be warned, if your chocolate is too hot the Jello will melt. you can use the tines of a fork to create a crisscross pattern on the top of each Jaffa Cake should you desire.
They tasted surprisingly good, even if the disk cutting and chocolate icing was remarkably fiddly.