Preheat the oven to 375°F. Butter an 8- or 10 -inch round baking dish.

Combine the flour and sugar in the bowl of a food processor. All ingredients should be cold. Add the chilled butter in pieces and process for approximately 10 seconds, or until the mixture resembles coarse meal. (To mix by hand, combine the dry ingredients in a large mixing bowl. Using a pastry blender or two table knives, cut in the butter until the mixture resembles coarse meal.)

While the machine is running, add the egg yolk and the ice water, a few drops at a time, through the feed tube, just until the dough holds together without being wet or sticky. Do not overprocess; 30 seconds should be sufficient. Test the dough at this point by squeezing a small amount together. If it is too crumbly, add a bit more water.

Place the dough on a piece of plastic wrap and press it into a flat circle with your fists. (This makes rolling easier than if the pastry is chilled as a ball.) Wrap and chill well, at least 1 hour.

Wash and dry the fruit. Cut into wedges and place in the prepared baking dish. Sprinkle the fruit with 3 tablespoons of the vanilla sugar and dot with the butter.

Roll out the dough large enough to cover the top of the baking dish. Place the dough over the fruit and pinch around the edge of the baking dish to seal. Trim the excess dough. Make 4 or 5 slits in the dough to allow the steam to escape and sprinkle with the remaining sugar. Bake 45 minutes until the crust is golden brown. Serve warm or cooled.