How to Make It
In a bowl, combine the flour, sugar and salt. Using a pastry cutter or 2 knives, cut in the butter until the mixture resembles coarse meal. Beat the egg with the milk and add to the bowl. Stir gently just until a dough forms. Divide the dough in half and shape each half into a disk. Wrap the disks in plastic and refrigerate until thoroughly chilled, at least 4 hours or overnight.
On a lightly floured surface, roll out 1 disk of dough to a 12-inch round. Cut out four 4-inch rounds and arrange them on a baking sheet. Repeat with the remaining dough. Cover with plastic and freeze until firm, for up to 3 days.
Preheat the oven to 375°. Arrange eight 4- to 5-inch gratin dishes on 2 baking sheets. In a saucepan, boil the sugar and water over moderate heat until deep amber, about 10 minutes. Remove the caramel from the heat and stir in the butter until smooth.
Pour 2 tablespoons of the caramel into each gratin dish and add 3 fig halves, cut side down. Set a frozen disk of dough on each dish to cover the figs. Bake for about 40 minutes, or until the dough is golden and the caramel is bubbly. Carefully unmold the tarts onto plates, pastry side down. Top each with a scoop of Raspberry Sorbet and serve.