Tomato and Corn Pie

Ingredients

• 2 to 2 ¼ cups all-purpose flour
• 1 T baking powder
• 1 3/4 t salt, divided
• 6 T cold unsalted butter, cut into 1/2-inch cubes
• 3/4 cup cold whole milk
• 1/2 cup mayonnaise
• 2 T fresh lemon juice
• 1 3/4 pounds beefsteak tomatoes, large dice (about 4 large)
• 1 1/2 cups corn (from about 2 ears), coarsely chopped by hand, divided
• 2 T finely chopped basil, divided
• 1 T finely chopped chives, divided
• 1/4 t black pepper, divided
• 7 ounces coarsely grated Smoked Fontina (1 3/4 cups), divided
• 1 egg for egg wash