Preheat oven to 180 °C / 350F.
Break eggs into a large bowl. Add sugar and, using an electric beater, beat until the mixture forms a thick ribbon. This takes about 10 minutes. To incorporate the most air, make large movements with the beater.
Add sifted flour all at once and, using a rubber spatula, fold in gently but quickly. When you see that the last of the flour has disappeared, incorporate the melted butter quickly, but gently.
Pour the mixture into the prepared tin and smooth the top with a spatula.
Bake in preheated oven for 35 - 40 minutes for the large cake or about 30 minutes for the smaller ones. Test the sponge by pressing lightly in the centre. If the sponge springs back, it is done.
When the sponge is cooked, remove from the oven and leave to cool for a few minutes before gently unmoulding onto a cooling rack.
Per serving: 103 Calories (kcal); 10g Total Fat; (84% calories from fat); 4g Protein; trace Carbohydrate; 143mg Cholesterol; 38mg Sodium Food Exchanges: 0 Grain(Starch); 1/2 Lean Meat; 0 Vegetable; 0 Fruit; 1
1/2 Fat; 0 Other Carbohydrates