How to make
Separate the egg yolks from the whites. Beat the egg yolks with the sugar to graying and add the milk while stirring, then the flour that you've sifted with the baking powder and baking soda, and lemon zest and candied lemons.
Separately, beat the egg whites with a pinch of salt to hard snow, then carefully mix them in with the other mixture. Put the batter into a greased and floured cake form. Bake in a moderately heated oven at about 360°F (180 °C) until ready.
Leave the sponge cake for 10 minutes in the form, invert it onto a tray and sprinkle it with powdered sugar, if desired.