How to Make It
Preheat the oven to 375°. In a large bowl, toss the eggplants and onion with 1/4 cup of the olive oil and the vinegar; season with salt and pepper. Spread the vegetables on a rimmed baking sheet and roast for about 20 minutes, turning occasionally, until tender and browned.
Meanwhile, in a large pie plate, toss the bread crumbs with the Parmesan and sage. Put the flour and eggs in 2 separate pie plates. Season the veal cutlets with salt and pepper, then dredge lightly in flour and dip in the eggs, letting any excess drip back into the plate. Dredge the cutlets in the bread crumbs, pressing lightly to help the crumbs adhere.
In a very large skillet, heat 1/2 cup of the olive oil until shimmering. Add half of the cutlets and cook over moderately high heat, turning once, until cooked through and crisp, about 4 minutes. Transfer to a platter and keep warm. Add the remaining 1/2 cup of olive oil to the skillet and fry the remaining cutlets. Serve the veal cutlets with the eggplant and onion.