For the tomato basil sauce:
1 tablespoon olive oil
3 tablespoons butter
1 small onion, finely chopped
2 large cloves garlic, finely chopped
1 cup chicken stock
2 cans San Marzano tomatoes (28-32 ounces each)
2 cups passata
A few leaves of torn basil
Sea salt, to taste
1 cup fine breadcrumbs
1 cup panko breadcrumbs
1 cup grated Parmigiano Reggiano cheese, divided
Zest of 1 lemon
1/4 cup flat-leaf parsley, finely chopped
2 tablespoons fresh thyme, finely chopped
Flour, for dredging
3 eggs, beaten
2 boneless, skinless chicken breasts, halved across forming 4 large cutlets, then pounded very thin
8 thin slices fior di latte cheese or fresh mozzarella cheese
Olive oil, for shallow frying
1 pound spaghetti, for side dish (optional - crusty bread is fine for mopping as well)
Salt the eggplant and drain on paper or kitchen towels for 20 minutes. Pat dry.
Heat the oil over medium-low heat and melt the butter. Add the onion and garlic and cook, covered, until very soft, 8-10 minutes, stirring occasionally. Raise the heat a bit and add the stock, tomatoes and passata. Bring to a bubble, then break up the tomatoes and add the basil. Simmer, uncovered, for 30 minutes; season with sea salt, to taste.
Combine the breadcrumbs, cheese, lemon zest and herbs in a shallow dish. Pour the flour into a second dish and beat the eggs in a third.
Season the pounded chicken cutlets with salt and pepper. Form a sandwich with one eggplant slice, two slices mozzarella and one chicken cutlet, covering the cheese completely. Coat the sandwiches with the flour, egg then breadcrumbs.
Heat the oil, about a quarter-inch, for shallow frying over medium to medium-high heat. Fry the sandwiches two at a time until cooked through and deeply golden, 8-10 minutes, turning occasionally. Keep warm on a rack set over a baking sheet in a warm oven at 275°F. Repeat with the remaining sandwiches.
Raise the oven heat to 375°F.
Spread some sauce in a casserole dish and shingle in the sandwiches. Top with a little more sauce and sprinkle with the remaining Parmigiano Reggiano; bake until golden.
Cook some spaghetti to al dente or char some bread to pass at the table. If you make the spaghetti, drain it and toss with a cup of reserved starchy cooking water, some tomato sauce, butter and extra cheese. Pass the remaining sauce at the table with the stuffed eggplant and chicken parm.