First of all, preheat the oven to 180°C.
In a food processor or with electric whisks, beat eggs and sugar together until smooth, light and creamy: it will take some time to reach the desired consistency, more or less 15 mins, so don't give up too early.
Please don't throw away your leftover egg whites: use them to make some delish meringues.
Incorporate the dry ingredients, sifted, with a delicate gesture and mix well. In a little pan or in the microwave melt the butter, then pour it over the cake batter and mix.
Pour into a greased and floured spring-release tin (12 cm diameter) and bake for about 35-40 mins or until golden brown.
Allow the cake to cool, then gently free it from the tin and flip it onto a serving plate.
Sprinkle the cake with icing sugar and serve.