Concord Grape Tart

Name: Concord Grape Tart
Ingredients: 2 ½ cups unbleached all-purpose flour, plus more for dusting; ¼ cup granulated sugar; ¾ teaspoon kosher salt; 2 sticks (1 cup) cold unsalted butter, cut into pieces; 1 large egg yolk; ¼ cup ice water; ¾ pound Concord grapes, stems removed; ½ cup plus 1 tablespoon water; ½ cup plus 2 tablespoons granulated sugar; 1 ½ teaspoons fresh lemon juice; ¼ teaspoon kosher salt; 1 tablespoon cornstarch; 1 large egg, lightly beaten; Coarse sanding sugar, for sprinkling; Creme fraiche, for serving