1. Wash, dry, and pit the plums. Preheat the oven to 200 °C (392 °F).
2. Prepare a shortcrust pastry:
3. Make a well with the flour, place 2 egg yolks in the center, add the butter, 50 g of sugar, a pinch of salt, and half a glass of cold water. Quickly work the dough, then shape it into a ball and let it rest for 2 hours under a cloth.
4. Divide the dough into 2 unequal parts, two-thirds and one-third. Roll out the larger part with a rolling pin into a circle, about 3 mm thick. Butter a pie dish and line it with the rolled-out dough, leaving a 3 cm overhang. Prick the dough with a fork. Spread a layer of beaten egg white on the bottom of the tart. Bake for 2 minutes, until a white film forms. This will prevent the fruit from releasing too much liquid and soaking the pastry.
5. Fill the tart with the plums and sprinkle them with sugar. Cover with the second rolled-out dough and fold the excess dough from the bottom over the edges of the pie dish. Seal the edges with a fork. Brush the surface with a mixture of beaten egg yolk, milk, and a pinch of sugar. Place a cardboard chimney in the center of the pierced crust.
6. Bake for 30 minutes. Serve warm with fresh cream.