Line a baking sheet with parchment paper; set aside. For dough, in a small bowl pour the boiling water over saffron threads; let stand for 15 minutes. Add the ice cubes to chill the mixture; set aside. In a large bowl stir together the 2 cups flour, the 1/4 cup sugar, and the 3/4 teaspoon salt. Using a pastry blender, cut in butter until mixture resembles coarse cornmeal. In a small bowl combine egg yolk and 3 tablespoons of the saffron-water mixture. Stir egg yolk mixture into flour mixture. Stir in enough of the remaining saffron-water mixture, 1 tablespoon at a time, to just moisten the flour mixture. Gather mixture into a ball, kneading gently until it holds together; flatten into a disk. Wrap in plastic wrap. Chill for 30 minutes to 3 days. On a lightly floured surface, roll dough into a 13-inch circle. Transfer to the prepared baking sheet; cover with plastic wrap and set aside.
Preheat oven to 375 degrees F. For filling, in a large bowl gently toss together pears, dried cherries, and lemon juice. Add the 2 tablespoons sugar, the 1 tablespoon flour, the cardamom, and the dash salt; gently toss to combine.
For pear syrup, in a small saucepan combine pear nectar, the 3 tablespoons sugar, and the crystallized ginger. Bring just to boiling over medium heat; reduce heat. Simmer, uncovered, for 5 minutes. Add to fruit mixture; toss gently to coat.
Spoon fruit mixture onto dough circle, leaving a 2-inch border of dough around the edge. Fold dough edge up and over fruit mixture, pleating as needed and leaving center uncovered. Spoon any liquid remaining in the bowl over fruit mixture. Brush dough edge with milk; sprinkle with additional sugar. Cover the fruit in center of tart with foil.
Bake for 45 to 60 minutes or until dough is golden and filling is bubbly. Cool on baking sheet on a wire rack. If desired, serve with ice cream.