1Tip all the ingredients into a bowl and beat until smooth. Divide mixture between the sandwich tins and level the surfaces.
2Bake the cakes in the centre of a preheated oven - 180°C (350°F, gas mark 4) for 20-25 mins, or until the cakes have risen and are golden, and spring back when lightly pressed in the centre.
3Remove the cakes from the oven and leave them to cool in the tins for 5-10 mins, then turn them out on to a wire rack and leave them to cool completely.
4Spread the jam over the base of one of the cakes. Lightly whip the double cream and spread it over the base of the other cake. Sandwich the two cakes together. Dredge with caster sugar before serving.