3/4 cup shredded manchego cheese
2 tablespoons extra-virgin olive oil
1 large onion, thinly sliced
2 1/4 pounds mixed heirloom tomatoes
3/4 cup shredded mozzarella cheese
1/4 cup mayonnaise
3 tablespoons breadcrumbs
3 tablespoons chopped fresh basil
3 tablespoons chopped fresh chives
3 tablespoons chopped fresh parsley
1 teaspoon chopped fresh thyme
Freshly ground pepper
Make the filling: Heat 1 tablespoon olive oil (I like the Tuscan flavored) in a large skillet over medium heat. Add the onion and cook, stirring, until golden, about 15 minutes. Let cool. Meanwhile, thinly slice the tomatoes; toss with 1 teaspoon kosher salt in a colander. Let drain, gently tossing occasionally, about 30 minutes.
Heat oven temperature to 375 degrees F. Combine the 3/4 cup manchego, the mozzarella, mayonnaise, breadcrumbs, 2 tablespoons each basil, chives, parsley, thyme and 1/4 teaspoon each kosher salt and pepper, and the sautéed onions in a bowl. Spread in the crust. Arrange the tomatoes on top. Drizzle with the remaining 1 tablespoon olive oil and season with pepper. Bake until the tomatoes are browned, about 40 minutes. Top with the remaining 1 tablespoon each basil, chives and parsley.