Grape & Apple Pie

INGREDIENTS

• 1/2 cup vegetable shortening
• 1 cup (2 sticks) chilled unsalted butter, cut into 1/2" cubes
• 3 cups all-purpose flour plus more for surface
• 3/4 cup plus 2 tablespoons sugar
• 1 pound red or black grapes, halved, seeded if needed
• 3 pounds tart, crisp apples (such as Crispin or Pink Lady), peeled, quartered, cored, thinly sliced
• 1 tablespoon sugar
• Vanilla ice cream (optional)
• 1 1/2 teaspoons kosher salt
• 2 tablespoons all-purpose flour