1/4 cup fresh ricotta, preferably sheep's or goat's milk
1/4 cup coarsely grated ricotta salata (2 ounces)
1 tablespoon minced chives
2 small tomatoes, cut into thin wedges
1 cup baby lettuces
2 tablespoons toasted pine nuts
Arrange the eggplant slices in a single layer on 2 baking sheets and sprinkle all over with 2 tablespoons of kosher salt. Let the eggplant slices stand for 3 hours. Thoroughly rinse the eggplant and transfer the slices to a clean kitchen towel. Squeeze the eggplant dry.
In a glass or ceramic jar, mix the olive oil with the sherry and balsamic vinegars, garlic and crushed pepper; season with salt and pepper. Add the eggplant, cover and refrigerate for 2 days.
In a large saucepan, heat 1 tablespoon of the olive oil. Add the leeks, garlic, potato and fennel. Cover and cook over low heat until tender, about 10 minutes. Add the romaine and Bibb lettuces and toss just until wilted, about 30 seconds. Transfer the contents of the saucepan to a blender. Add the vegetable stock, parsley and the remaining 3 tablespoons of olive oil and puree. Strain the soup through a fine sieve into a medium bowl. Stir in the lemon juice and season with salt and pepper. Refrigerate the lettuce soup until chilled.
In a small bowl, blend the fresh ricotta with the ricotta salata and chives and season with salt and pepper.
Ladle the soup into bowls. Garnish with eggplant rounds and tomato wedges. Using 2 spoons, form the cheese mixture into 8 quenelles and place 2 in each bowl. Scatter the baby lettuces and pine nuts over the soup and serve.
The pickled eggplant can be refrigerated for up to 1 month. The soup and the ricotta topping can be refrigerated overnight.