Preheat the oven to 180°C.
Brush two 15cm-17.5cm cake tins with melted butter and line the bottoms with greaseproof paper.
Cream the butter and sugar in a large bowl until pale and fluffy.
Beat in the eggs individually, adding a little flour if the mixture starts to curdle.
Fold in the flour using a metal spoon without over-mixing.
Divide the batter between the tins and level the tops with a spatula.
Bake for 20 minutes until golden and the sponges spring back when touched.
Cool in the tins for 10 minutes then transfer to a wire rack to cool completely.
Spread one sponge with jam and whipped cream then top with the second sponge.
Dust the top with icing sugar and serve.