You will need:
– 150g self-raising flour – 150g sugar
– 100g butter – 2 eggs
– 1/4 tsp baking powder – zest of 1 lemon
– string – juice of 1 lemon
Put one lidded pot inside another, slightly bigger pot on a bed of gravel and water (due to the gravel, don’t be using your best non-stick pan). Grease the inner pan with a little butter.
Mix the remaining butter with the dry ingredients. Crack in the eggs and beat together until smooth and light. Add the lemon.
Tie-up the inner pan as a parcel, using the string. Lower this pan into the bigger pan of boiling water (on gravel) – the water should go half-way up the side of the pan when the inner parcel is fully lowered in, but make sure it doesn’t boil dry during the next half hour.
Let the dish boil away and check after 25 minutes. If it’s still of a gooey consistency then re-seal and give it an extra 10 minutes – it will be cooked if you poke a stick through the middle and it comes out clean.
When it’s cooked, serve on a plate – as you would any normal sponge cake.
If you want to just use a conventional oven, heat it to 160-170 celcius and just use the internal pan for 25-30 minutes.
If you don’t cook it on a campfire (or in an oven, as above), you can use the parcel technique on a hob.