Pie Shell:
1 cup unbleached all –purpose flour
½ cup whole wheat flour
1 tablespoons finely chopped fresh herbs, such as a combination of thyme, chives and parsley
½ teaspoon fine sea salt
8 tablespoons (1 stick) unsalted butter, chilled, cut into ½ inch cubes
½ cup yogurt or sour cream
2 tablespoons Dijon mustard, for brushing the shell

Filling
4 medium carrots, scrubbed, unpeeled, and shredded, about 2 ½ cups
2 tablespoons dry sherry
1 tablespoon unsalted butter or olive oil
1 medium red onion, thinly sliced into half-moons
¼ cup shredded Vermont Cheddar cheese
1 cup half and half
2 large eggs plus 1 large egg yolk
1 tablespoons finely chopped fresh tarragon
¼ teaspoon fine sea salt
1/8 teaspoon freshly ground pepper

Position a rack in the center of the oven and preheat to 400*F. To make the dough, pulse the all-purpose and whole-wheat flours, herbs and salt in a food processor to combine. Add the butter and pulse until the mixture resembles coarse cornmeal with a few pea sized pieces. Turn off the machine and add the yogurt. Pulse just until the dough comes together into a ball. Roll out the dough on a lightly floured surface into a 12-inch round about 1/8 -inch thick. Transfer to a lightly buttered 9-inch tart pan. Prick the dough in several places with a fork. Line the dough with a piece of aluminum foil, and fill with fried beans, raw rice or commercial pie weights.

Bake until the dough looks set but not browned, about 12 minutes. Lift up and remove the foil with the beans. Transfer the pan to a wire cake rack to cool slightly. Bring a medium saucepan of lightly salted water to a boil over high heat. Add the carrots and cook until they are bright orange and tender, about 1 minute. Drain well. Transfer to a medium bowl and toss with 1 tablespoon of the sherry. Melt the butter in a medium skillet over medium heat. Add the onion and cook until tender, about 5 minutes. Stir in the carrots and cook for 1 minute to combine the flavors. Cool slightly.

Using the back of a spoon or a pastry brush, paint the mustard inside the pie shell. Sprinkle with the cheese and top with the carrots. Whisk the half-and-half, eggs, yolk, tarragon, remaining 1-tablespoon sherry and the salt and pepper in a medium bowl until combined. Pour into the pie shell. Place the quiche on a baking sheet. Bake until the custard seems set when you give the pan a gently shake, about 30 minutes. Cool for about 10 minutes, then slice and serve warm or room temperature.