In a large bowl, knead all the ingredients except the plums and the jam.
Form a dough ball and refrigerate for about half an hour.
Roll out the shortcrust pastry in the pan lined with parchment paper and prick with a fork.
Fill with plum jam, arrange the plum slices, and press the edge inward.
Bake at 180°C for about 40 minutes in a preheated oven. Always do the toothpick test.
Italy, Campania