Blend all the ingredients together to form a uniform mixture. Leave to rest for 12 hours.
Boil the milk with the lemon rind. Beat the egg yolks together with the sugar, add the flour and gradually pour in the milk, mixing carefully with a whisk to avoid lumps. Boil the custard for 3 minutes. Leave to cool.
Asembling the cake
Roll out the dough with a rolling pin, using a little flour to ensure the dough does not stick, and cut out circles. Spread the custard over the circles, add two Amarena cherries. Cover with the rest of the dough and cut into a round form. Place on a baking tray, leave to rise for 20 minutes and brush with egg yolk and a pinch of sugar.Bake in the oven for 18 minutes at 180°C. Sprinkle with icing sugar and serve warm.