How to cook
Beat the butter with the sugar until they turn white. Add 2 eggs, one at a time, and then 3 egg yolks.
Add the flour, raisins, rum and the grated rind of 1 lemon.
Finally add the 3 egg whites, beaten to snow. Bake for about 50 minutes, the first 10 minutes at 392°F (200°C), then at 320°F (160 °C) until ready.