Bring skim milk to a boil with salt and lemon zest. Stir in cornmeal and let swell over low heat for 15 minutes. Allow the mixture to cool. Cream yolks with butter, add juice of half a lemon, whip egg whites with raw sugar and fold into cornmeal mixture with yolk mixture. Grease baking dishes (4 – 6 cm) with melted butter, sprinkle with raw sugar and let the mixture cook at 220 °C for about 25 minutes. For the berry sauce, bring the berries to the boil with the honey and water, mix well and strain through a hair sieve. Turn the casseroles out onto hot plates and serve with berry sauce.