Preparation Whisk together flour, baking powder, and 3/4 teaspoon salt in a bowl, then blend in 3/4 stick cold butter with your fingertips or a pastry blender until it resembles coarse meal. Add milk, stirring until mixture just forms a dough, then gather into a ball. Divide dough in half and roll out 1 piece between sheets of plastic wrap into a 12-inch round (1/8 inch thick). Remove top sheet of plastic wrap, then lift dough using bottom sheet of plastic wrap and invert into a 9-inch glass pie plate, patting with your fingers to fit (there will be just enough dough to line plate without an overhang). Discard plastic wrap. Preheat oven to 400°F. Whisk together mayonnaise and lemon juice. Arrange half of tomatoes in crust, overlapping, and sprinkle with half of corn, 1 tablespoon basil, 1/2 tablespoon chives, 1/8 teaspoon pepper, and 1/2 teaspoon salt. Repeat layering with remaining tomatoes, corn, basil, chives, pepper, and salt, then sprinkle with 1 cup cheese. Pour lemon mayonnaise over filling and sprinkle with remaining cheese. Roll out remaining piece of dough into a 12-inch round in same manner, then fit over filling, folding overhang under edge of bottom crust and pinching edge to seal. Cut 4 steam vents in top crust and brush crust with 2 teaspoons melted butter. Bake pie in middle of oven until crust is golden and filling is bubbling, 30 to 35 minutes, then cool on a rack. Serve warm or at room temperature. Cooks' note:·Pie can be baked 1 day ahead and cooled completely, then chilled, covered. Reheat in a preheated 350°F oven until warm, about 30 minutes.
Preparation Whisk together flour, baking powder, and 3/4 teaspoon salt in a bowl, then blend in 3/4 stick cold butter with your fingertips or a pastry blender until it resembles coarse meal. Add milk, stirring until mixture just forms a dough, then gather into a ball. Divide dough in half and roll out 1 piece between sheets of plastic wrap into a 12-inch round (1/8 inch thick). Remove top sheet of plastic wrap, then lift dough using bottom sheet of plastic wrap and invert into a 9-inch glass pie plate, patting with your fingers to fit (there will be just enough dough to line plate without an overhang). Discard plastic wrap. Preheat oven to 400°F. Whisk together mayonnaise and lemon juice. Arrange half of tomatoes in crust, overlapping, and sprinkle with half of corn, 1 tablespoon basil, 1/2 tablespoon chives, 1/8 teaspoon pepper, and 1/2 teaspoon salt. Repeat layering with remaining tomatoes, corn, basil, chives, pepper, and salt, then sprinkle with 1 cup cheese. Pour lemon mayonnaise over filling and sprinkle with remaining cheese. Roll out remaining piece of dough into a 12-inch round in same manner, then fit over filling, folding overhang under edge of bottom crust and pinching edge to seal. Cut 4 steam vents in top crust and brush crust with 2 teaspoons melted butter. Bake pie in middle of oven until crust is golden and filling is bubbling, 30 to 35 minutes, then cool on a rack. Serve warm or at room temperature. Cooks' note:·Pie can be baked 1 day ahead and cooled completely, then chilled, covered. Reheat in a preheated 350°F oven until warm, about 30 minutes.