Martha Stewart's Slab Pie

INGREDIENTS

• 1/4 cup cornstarch
• Juice of 1/2 a lemon (about 1 tablespoon)
• 2 teaspoons sugar
• 1 1/4 cup granulated sugar
• 1/4 teaspoon salt
• 5 cups all purpose flour
• 12 to 16 tablespoons ice water
• All purpose flour, for dusting
• Pate Brisee (recipe below)
• 6 cups fresh sour cherries, stemmed and pitted; or 6 cups fresh mixed berries; or 7 medium peaches, cut into 1/2-inch pieces (about 8 cups)
• 1/4 cup sanding sugar (or granulated sugar)
• 1 pound (4 sticks) cold unsalted butter, cut into small cubes
• 1 tablespoon coarse salt