Crust: 1 3/4 cups all-purpose flour, plus more for dusting 2 tablespoons sugar 1/2 teaspoon fine salt 12 tablespoons (1 1/2 sticks) chilled unsalted butter, diced and kept very cold 4 teaspoons cider or white vinegar 1/3 cup ice water, plus more if needed Filling: 1/2 cup chopped scallions 1/2 cup shredded roasted turkey 1…