To prepare crust: Pulse pecans in a food processor until finely ground. Combine with whole-wheat pastry flour, all-purpose flour, sugar and salt in a medium bowl. Cut in butter with a pastry blender or your fingers until the mixture resembles coarse crumbs with a few larger pieces. Add oil and stir with a fork to blend. Mix 1/4 cup water, egg yolk and lemon juice (or vinegar) in a measuring cup. Make a well in the center of the flour mixture. Add enough of the wet ingredients, stirring with a fork, until the dough clumps together. (Add a little water if it seems too dry.) Turn the dough out onto a lightly floured surface and knead several times. Form into a ball, then flatten into a disk. Wrap in plastic wrap and refrigerate for at least 1 hour.

Position rack in lower third of oven; preheat to 400 degrees F. Coat a 9-inch pie pan with cooking spray.

To prepare filling & assemble pie: Combine sugar, milk, yogurt, eggs, flour, cornstarch, vanilla (or almond) extract and salt in a medium bowl; whisk until smooth.

Roll out the dough between sheets of parchment or wax paper into a 12-inch circle. Peel off the top sheet and invert the dough into the prepared pie pan. Peel off the remaining paper. Trim the dough so it overhangs evenly by about 1 inch. Fold the edges under to make a plump edge; flute or crimp the edge with your fingers (see Tip) or a fork. Place on a baking sheet.

Arrange peaches in the crust and pour the filling on top (some peaches will float but this won't affect the final results). Bake for 30 minutes.

Remove the pie from the oven and sprinkle chopped pecans over the top. Cover the edges with heavy-duty foil (or a double layer of regular foil) to help prevent overbrowning. Reduce oven temperature to 350 degrees . Return the pie to the oven and bake until a knife inserted in the center comes out clean, 40 minutes to 1 hour more. Let cool for 1 1/2 hours. Serve warm or refrigerate until cold.