Preheat oven to 180°C (350°F). Sift the flour 3 times. Set aside. Place the eggs and sugar in the bowl of an electric mixer and beat for 8–10 minutes or until thick and pale and tripled in volume. Sift the flour over the egg mixture and gently fold through.* Fold through the butter. Grease 2 x 20cm-round cake tins and line the bases with non-stick baking paper.
Pour half the mixture into each tin and bake for 25 minutes or until the cakes are springy to touch and come away from the sides of the tin. Cool on wire racks. Fill with whipped cream and jam of your choice. To serve, sprinkle with extra sugar. Serves 8–10.
* For a light and airy sponge, use a metal spoon to fold the flour through the egg mixture with a gentle cutting, lifting and folding action.
** Try using sliced berries or stone fruit and cream as the sponge filling instead of jam and cream. Lemon curd would be equally as delicious, too.
*** You can also use this recipe to make one thick sponge. Pour mixture into a deep 18cm-square square cake time and bake as above.