Tomato, Cheddar And Bacon Pie

Ingredients

• 2 cups all-purpose flour
• 1 + 1/2 teaspoons baking powder
• 1/2 teaspoon baking soda
• 1/2 teaspoon kosher salt
• 6 tablespoons chilled unsalted butter, cut into 1/2' cubes
• 1 cup buttermilk
• 2 pounds large ripe tomatoes, cored, seeds removed and cut into 1/4' slices
• 2 + 1/2 cups extra-sharp cheddar, grated
• 1/4 cup parmesan cheese, grated
• 4 ounces cream cheese, softened
• 1/3 cup mayonnaise
• 1 scallion, diced
• 1/4 cup fresh basil, chopped
• 1 tablespoon white wine vinegar
• 2 teaspoons sugar
• 3/4 teaspoon kosher salt
• 1/2 teaspoon freshly ground black pepper
• 1 - 2 tablespoons cornmeal, for sprinkling over crust
• thick-sliced bacon, cooked, for serving, optional