Heirloom Tomato Pie

From the Food Network Magazine posting for my sister.

• Ready In: 50 mins
• Serves: 6

Ingredients

• 1  cup all-purpose flour
• 3⁄4 cup yellow cornmeal
• 3⁄4 teaspoon fine salt
• 1⁄2 cup unsalted butter, cut into 1/2-inch pieces
• 3⁄4 cup manchego cheese, shredded plus
• 3  tablespoons manchego cheese, shredded
• 2  tablespoons extra virgin olive oil
• 1  large onion, thinly sliced
• 2 1⁄2 lbs  mixed  heirloom tomatoes
•  kosher salt
• 3⁄4 cup mozzarella cheese, shredded
• 1⁄4 cup mayonnaise
• 3  tablespoons  breadcrumbs
• 3  tablespoons fresh chives, chopped
• 3  tablespoons fresh parsley, chopped
• 1  teaspoon fresh thyme, chopped
•  fresh ground pepper

Directions

1. Prepare Crust:
2. In a bowl mix flour, cornmeal and salt together and put in a food processor.
3. Add cold butter and 3T of manchego pulse until coarse meal texture and pea-size bits of butter.
4. Slowly add 4 T of ice water until dough comes together, adding 1 T more of ice water if needed.
5. Place on plastic wrap and press into a disk shape.
6. Wrap well and refrigerate until firm, about 45 minutes.
7. Roll between 2 sheets parchment paper into a 13" round circle.
8. Put into a 9 1/2" deep-dish pie plate.