Very easy and only takes one egg (I always find I never have quite enough eggs in the house for impulse baking!). I have tracked it down and found out that it is from WigWamBam (thank you!):
8oz self raising flour
pinch of salt
4oz butter or margarine
2oz raisins
2 eating apples, peeled, cored and roughly chopped
3 oz granulated sugar
1 egg, beaten
2 tablespoons milk
Sift the flour and salt, rub in the butter until it resembles breadcrumbs
Stir in the raisins, apples and sugar
Add the egg and milk, mix with a knife. The dough will be soft.
Spoon the mixture into a greased 8" sandwich tin
Bake at 180C for about 50 minutes, or until a skewer inserted into the middle comes out clean. You may need to cover the cake with tin foil if it cooks too quickly on the outside.
Cool in the tin. When you turn it out, sprinkle with extra sugar.