Tomato Quiche

1 homemade or store bought deep dish pie crust
2 1/4 pounds assorted heirloom tomatoes, thinly sliced
1 1/4 teaspoons kosher salt, divided
1 sweet onion, chopped 
1 1/4 teaspoons freshly ground pepper, divided
1 tablespoon canola oil 
1/2 cup assorted chopped fresh herbs (such as chives, parsley, and basil)
1/2 cup freshly grated Gruyère cheese
1/2 cup freshly grated Parmigiano-Reggiano cheese
1/4 cup mayonnaise

• Preheat oven to 350°.

• Place tomatoes in a single layer on paper towels; sprinkle with 1 tsp. salt. Let stand 10 minutes.

• Meanwhile, sauté onion and 1/4 tsp. each salt and pepper in hot oil in a skillet over medium heat 3 minutes or until onion is tender.

• Pat tomatoes dry with a paper towel. Layer tomatoes, onion, and herbs in prepared crust, seasoning each layer with pepper (1 tsp. total). 

• Stir together cheeses and mayonnaise; spread over pie.

• Bake for 30 minutes or until lightly browned, shielding edges with foil to prevent excessive browning. 

• Serve hot, warm, or at room temperature.