In a saucepan, bring 400 ml of milk to a boil. In the remaining 100 ml, add the custard powder and sugar, then pour the mixture into the boiling milk. Cook over low heat, stirring constantly, until the cream thickens. If desired, add a tablespoon of butter. Let cool. 
Preparation of the dough for the pancakes:In a bowl, mix the ricotta, eggs, sugar, baking powder and a pinch of salt. You can add a banana for a slightly sweeter flavor. Blend until smooth. 
