Ingredients

  • 4 to 5 garden-ripe tomatoes, preferably heirloom, cored and thinly sliced
  • 1 1/2 teaspoons coarse kosher salt, for sprinkling, plus more as needed
  • One 9-inch pie plate lined with your favorite pie crust, unbaked
  • 1 tablespoon olive oil
  • 1 sweet onion, finely chopped
  • Freshly ground black pepper
  • 1/2 cup chopped mixed fresh herbs such as chives, parsley and basil
  • 1/2 cup freshly grated Gruyere (2 ounces)
  • 1/2 cup freshly grated Parmigiano-Reggiano (2 ounces)
  • 1/4 cup mayonnaise

Method

  • Position an oven rack in the lower third of the oven and preheat to 375 degrees F.
  • Place the tomatoes on a rack in the sink in 1 layer.
  • Sprinkle with the salt and allow to drain for 10 minutes.
  • Line the pie shell with foil and fill with pie weights, dried beans or rice.
  • Bake in the lower third of the oven for 20 minutes.
  • Carefully remove the weights and foil.
  • Return to the oven and bake until light golden, 10 minutes more.
  • Remove to cool in the pan on a wire rack.
  • Reduce the oven temperature to 350 degrees F. Heat the oil in a skillet over medium heat.
  • Add the onions and season with salt and pepper.
  • Cook until soft and translucent, 3 to 5 minutes.
  • (Don't skip this step!
  • Not cooking the onions will make the pie soggy and wet.)
  • Pat the tomato slices dry on both sides with paper towels.
  • Layer the tomato slices, cooked onions and chopped herbs in the baked pie shell.
  • Season each layer with pepper.
  • Combine the grated cheeses and mayonnaise together.
  • Spread the mixture on top of the tomatoes and bake until lightly browned, about 30 minutes.
  • Remove to a rack to cool.
  • Serve warm or at room temperature.