Rhubarb Galette

Rhubarb pie has always been a staple at my Mom's house and we have all experimented with new ways to use rhubarb over the years.  One of my favorites is Allison's stewed rhubarb served over vanilla yogurt....yumm.... I think I'll go make some.
           Crust
1/4 cup cold buttermilk
2 large eggs yolks
2 cups unbleached flour
1/2 cup fine-grind cornmeal
3 tablespoons confectioners' sugar
1/2 teaspoon salt
16 tablespoons very cold unsalted butter, cut into 1/4 inch dice

          Filling
2 pound rhubarb, washed, tops and bottoms trimmed, and cut
   into 1/2 inch dice (about 6 generous cups)
1 1/2 cups granulated sugar
1 Tablespoon finely grated lemon zest from 1 lemon
1 vanilla bean, split in half lengthwise, seeds remove, seeds and pod reserved
2 tablespoons cornstarch
2 tablespoons unsalted butter, cut into 1/4 inch dice
4 tablespoons sugar
2 tablespoons whole milk
   Whipped Cream or Vanilla Ice Cream for serving

For the Crust: Whisk the buttermilk, egg yolks, and 1 tablespoon water together in a medium bowl.   Set aside.  In the bowl of a standing mixer fitted with the paddle attachment, combine the flour, the butter and mix on low speed until the mixture resembles coarse crumbs with pieces of butter the size of Grape-nuts cereal, about 1 minute.  With the mixer running on low speed, slowly add the buttermilk mixture.  Mix on low until the dough comes together, about 20 seconds (do not over mix).  Remove the dough from the mixer, form into an 8-inch disk, cover with plastic wrap, and refrigerate until firm, about 1 hour.

For the Filling: Cook the rhubarb, sugar, lemon zest, and vanilla seeds and pod in a 12 inch skillet over high heat, stirring frequently, until the rhubarb releases its juices, about 3-4 minuets. It is 4-5 minutes from the time you turn on the stove until you are finished.  Rhubarb will still be firm and easily holding its shape when done.  Discard the vanilla pod and drain the mixture in a fine-mesh sieve set over the medium bowl, reserving the juices.  Transfer the drained rhubarb to a rimmed baking sheet and cool completely at room temperature, about 30 minuets.  Transfer the cooled rhubarb to a medium bowl, stir in the cornstarch and butter, and set aside.

Meanwhile, simmer the reserved rhubarb juices in a small saucepan over medium high heat until syrupy and reduced to 1/2 cup, 3 to 5 minutes.  Transfer to a small bowl and cool at room temperature.

To assemble the galette: Adjust an oven rack to the middle position and heat the over to 350 degrees. Roll the dough out on a lightly floured silpat or parchment paper, to a 16-inch round, about 1/4 inch thick, trimming and discarding any excess dough.  Transfer the dough to a rimless baking sheet (or an inverted rimmed baking sheet).  Evenly sprinkle 2 tablespoons of the sugar over the crust, leaving a 3 inch border.  Carefully spread the filling evenly over the sugar, leaving the 3 inch boarder.  Carefully spread the filling evenly over the sugar, leaving the 3-inch boarder uncovered.  Fold the boarder of the dough up over the rhubarb in overlapping folds.  Brush the top crust with the milk and sprinkle with the remaining 2 tablespoons sugar.  Bake until the crust is golden and the rhubarb filling is bubbling, 45 to 55 minutes.  Cool the galette on the baking sheet for 30 minutes.

To serve: Slide the galette onto a cutting board, removing the parchment paper, and slice into 8 wedges.  Serve immediately, with the cooled rhubarb syrup and the Whipped Cream or vanilla ice cream.