Caramelized Onion AND Tomato PIE

Let's Cook

1. Step 1.

   Melt 2 tablespoons unsalted butter in a 10-inch skillet over medium-low heat. Add 2 thinly sliced large yellow onions and cook, stirring often, until deeply caramelized to a rich dark brown, 25 to 35 minutes. Stir in 2 minced medium garlic cloves and 1 tablespoon chopped fresh thyme (or 1 teaspoon dried) and cook for 1 minute. Season with kosher salt and freshly ground black pepper to taste. Transfer the onion mixture to a large bowl and let cool slightly.

2. Step 2.

   While the onions cool, preheat the oven to 425°F.

3. Step 3.

   Roll the prepared pie dough out into a 14-inch circle. Transfer the crust to the same 10-inch skillet, pressing it into the bottom and sides of the pan. Fold the edges under and crimp as desired.

4. Step 4.

   Fold 2 cups (about 6 ounces) shredded Parmesan cheese, ½ cup mayonnaise, and 1 large beaten egg into the cooled onion mixture until well combined.

5. Step 5.

   Spread one-third of the onion-cheese mixture onto the bottom of the pie crust. Sprinkle with 1 tablespoon dried bread crumbs. Arrange half of the 2 pounds fresh tomatoes (cut into ¼-inch-thick slices) on top of the bread crumbs, overlapping slightly. Repeat with another one-third of the onion mixture, the remaining 1 tablespoon bread crumbs, and the remaining tomato slices. Top with the remaining onion mixture.

6. Step 6.

   Loosely cover the skillet with aluminum foil and bake for 15 minutes. Reduce the oven temperature to 375°F and continue baking until the filling is tender, about 30 minutes more. Remove the foil and bake until the bread crumbs are golden brown, 5 to 10 additional minutes. Cool in the skillet for 30 minutes before serving.