homemade tarte dough
Proof the yeast: In a small bowl, combine 1 cups warm water (105–110°F), 1 teaspoons granulated sugar, and 2.3 teaspoons active dry yeast (about 1 packet). Let stand until foamy.
Mix the dough: In a large bowl, whisk together 3 cups all-purpose flour, plus more for dusting and 1 teaspoons kosher salt. Add the yeast mixture and 2 tablespoons extra-virgin olive oil, plus more for brushing. Mix until a shaggy dough forms.
Knead the dough: Knead on a lightly floured surface until smooth and elastic (a stand mixer with a dough hook takes about 9 minutes).
First rise: Place the dough in a lightly oiled bowl, cover, and let rise until doubled in size.
Divide and rest: Punch down the dough and divide into 4 equal portions. Shape each into a ball and let rest.
Shape the dough: Roll each ball into an 8-inch circle, about 1/8th inch thick.

Store Bought Substitute: Trader Joe's Lavash Flatbread

piave mornay sauce
Melt the butter: For the mornay sauce, melt 2 tablespoons unsalted butter in a saucepan over medium heat.
Cook the roux: Whisk in 2 tablespoons all-purpose flour and cook until the raw flour smell cooks off and the roux has a lightly nutty aroma.
Thicken the sauce: Slowly whisk in 1 cups whole milk, warmed until smooth. Simmer until thickened.
Add the cheese: Remove from heat and stir in 3/4 cups finely grated Piave Vecchio cheese until silky.
Season the sauce: Season with 1 pinch kosher salt, to taste. Keep warm.

grilling nectarines & assebling the tartes for baking
Grill the nectarines: Brush 2 ripe but firm nectarines, cut into thin 1/4-inch slices with 1 tablespoons olive oil, for grilling nectarines and grill over medium-high heat until lightly caramelized, about 4 minutes per side.
Cook the flatbread crusts: Preheat a dry, ungreased cast iron pan or skillet over medium-high heat. Brush each rolled dough round lightly with olive oil and cook until puffed, with large air bubbles and light golden-brown spotting on both sides, about 2–5 minutes per side.
Assemble the tartes: Spread each flatbread generously with the warm Piave Vecchio sauce. Arrange the grilled nectarines over the sauce, then drape the prosciutto ribbons evenly across the top.
Bake the tartes: Transfer tartes onto the hot stone or a parchment-lined baking sheet and bake until warm and the prosciutto begins to lightly crisp, about 5-6 minutes.