1. Preheat the oven to 425°. Heat 1 tablespoon of the oil in each of 2 large ovenproof skillets until almost smoking. Season the eggplants with salt and arrange them in the skillets. Add a piece of butter to each and shake the pans over high heat to glaze the eggplants. Transfer the skillets to the oven and roast for about 40 minutes, or until tender and browned.
2. Meanwhile, wrap the garlic in foil and roast for about 25 minutes, or until softened. Squeeze the garlic from the skins into a small dish. Leave the oven on.
3. Working in 2 batches, puree the roasted eggplant with the garlic in a food processor. Scrape the puree into a bowl.
4. In a small skillet, toast the cumin seeds over moderate heat until fragrant, about 40 seconds. Transfer to a mortar or spice grinder and let cool, then grind to a powder. Stir the cumin and 1/2 teaspoon salt into the eggplant puree, then add the egg yolks, Pecorino and Fontina.
5. Butter a shallow 9-by-13-inch glass or ceramic baking dish. Sprinkle with 1 tablespoon of the Parmesan. In a large bowl, beat the egg whites with a pinch of salt until firm peaks form. Fold one-third of the beaten whites into the eggplant mixture, then gently fold in the remaining whites just until combined. Scrape into the prepared dish, sprinkle with the remaining 1 tablespoon of Parmesan and bake in the upper third of the oven for about 17 minutes, or until puffed and barely firm; serve.
Notes: If you can't find Pecorino pepato, use plain Pecorino and add 1 teaspoon of coarsely cracked pepper.