Tomato Soup With ‘Grilled Cheese’ Frichi
2 pounds vine-ripened tomatoes, hulled and halved if large
1 medium sweet onion, such as Vidalia, coarsely chopped
2 tablespoons extra-virgin olive oil
3/4 teaspoon kosher salt, plus more as needed
1/2 teaspoon freshly ground black pepper, or more as needed
1 cup dry white wine
4 ounces Gruyere cheese, finely grated
1/4 cup packed fresh cilantro, flat-leaf parsley or basil leaves, plus more, chopped, for garnish
Preheat the oven to 300 degrees.
Toss together the tomatoes, onion, oil, ½ teaspoon of the salt and ¼ teaspoon of the pepper on a rimmed baking sheet, until evenly coated. Roast (middle rack) until the tomatoes and onion are soft but not browned, about an hour. Increase the oven temperature to 400 degrees.
Transfer the mixture to a medium saucepan, add the wine and cook over medium-high heat until the liquid has reduced by half, stirring frequently to prevent scorching. Add enough water to barely cover the tomatoes, and stir in the remaining ¼ teaspoon of salt and ¼ teaspoon of pepper.
Once the mixture comes to a boil, reduce the heat to medium or medium-low so that the liquid is barely bubbling; cook, stirring occasionally, until the flavors come together and the mixture begins to thicken, about 20 minutes.
While the soup is cooking, make the "grilled cheese" frichi: Wipe clean the baking sheet you used for the tomatoes and onion, then line it with parchment paper or a silicone liner. Divide the grated cheese into four equal portions, and pile each on the sheet, leaving at least 2 inches between them. Roast (middle rack) until flat, lightly golden brown all over and crisp at the edges, 12 to 14 minutes. Let cool on the baking sheet for 5 minutes, then use a metal spatula to carefully transfer them to a plate to cool completely.
Once the soup has thickened, stir in the ¼ cup of herbs. Use an immersion (stick) blender to puree the soup until smooth. Increase the heat to medium; cook the soup for 5 minutes more. Taste, and add more salt and pepper, as needed.
To serve, divide the soup among bowls, and top each portion with a frico and some of the chopped herbs.