Cut the
courgettes into slices and cook in a pan with oil until brown. Melt some butter and mix with flour. Boil for one minute and carefully add the milk, stirring gently. Add salt and the grated nutmeg. Boil until suitably thick. Add the eggs, the Parmesan cheese, salt and the nutmeg to the mixture. Mix well and gently dot the fried squash.
Rub a double saucepan with butter and spray with flour and pour in the mixture. Heat it to 190 °C for 45 min. Allow to rest for a while before serving.