Special equipment: a 9-inch fluted tart pan, 1 inch deep, ideally with removable sides. Also pie weights or raw rice grains.
Free free to buy your crust!
Else make the pastry dough:
Pulse together all ingredients, until they form a ball. Wrap in plastic and chill in refrigerator for 15 minutes, to make it easier to work.
Roll out the dough between 2 sheets of plastic wrap into a very thin 11-inch round. Remove top sheet of plastic wrap and invert dough into tart pan, pressing gently to fit.
Build up some extra on the sides, as sides will shrink during baking. Avoid going over the edge of pan, as this will drop off and smoke in oven bottom.
Prick all over bottom of shell (but not sides) lightly with a fork, then chill in freezer 30 minutes.
Put oven rack in lower position and preheat oven to 340 F, on convention bake.
Egg wash the shell! Then line the chilled shell with buttered parchment paper (buttered side down) and fill with pie weights/uncooked rice.
Bake for just 10 minutes. This bake is to get the crust started, to avoid soggy crust!! Carefully remove weights and foil, crust will be delicate. Cool in pan on a rack, about 20 minutes.
Make the peach mixture:
Preheat oven to 340 F.
Peel and slice peaches into about 1/8ths.
Arrange the peach slices in overlapping circles on the crust, striving to cover it completely. Overfill a bit as the peaches will slightly shrink in baking.
Combine the egg yolks, milk, sugar, cornstarch, and flour and whisk until smooth. Pour over the peaches. Don't overfill the tart dish! But it will not rise during baking.
Shape a piece of aluminum foil by cutting a circle sufficient to cover the pan, and cut out most of the center. We want the foil to cover the crust at the edge.
Put pan on a baking sheet and bake for 1 hour, until the custard sets and is pale golden in color. Test after 50 minutes by shaking slightly and see the center is stiffened.
Let it cool before glazing.
Making the glaze:
Squeeze the juice out of one peach and pour through a strainer.
Heat and boil the juice and sugar in a sauce pin. Stir regularly. As it boils it will thicken slightly. When the spoon can pour and show it is no longer runny, remove from heat and immediately spoon over the tart. The mixture will solidify quickly so don’t hesitate. Don’t try to spread, just pour from the spoon.