To make the crust, pulse the flour, sugar, salt, and butter together in the bowl of a food processor fitted with a steel blade until crumbled. Then add the egg yolk, and pulse until the dough comes together.

Place the dough in the center of an ungreased 9-inch tart pan with a removable bottom.  Dust your fingers with flour, and gently press out the dough to cover the bottom and sides of the pan.  Refrigerate for at least 30 minutes.

Preheat the oven to 450°F, and bake the crust for 10 minutes. Reduce the oven to 375°F, and bake for another 5 minutes. Remove the crust from the oven, and let cool slightly. Reduce the oven temperature to 350°F.

Mix the jam with the brandy in a small bowl, and spread over the bottom of the crust. Pit the plums and cut them into four pieces each. Starting at the outside, arrange the plums in a circle so that all the pieces overlap, created concentric circles that wind into the center of the pan.  Sprinkle with the cinnamon and lemon zest.

Return the tart to the oven and bake for about 30 minutes, or until the crust is golden brown and the plums are juicy. Remove the tart from the oven, sprinkle on the sugar, and serve warm or at room temperature.