Note: These recipes have been adapted from "The Babbo Cookbook" by Mario Batali. Photography by Christopher Hirsheimer. Copyright 2002 by Mario Batali. Photographs copyright 2002 by Christopher Hirsheimer. Reprinted by permission of Clarkson Potter.
Cut liver into 12 cubes (1 1/2 to 2 inches), and place in a bowl with milk. Let soak, refrigerated, for 1 hour.
Cut caul fat into 12 squares (7 inches each). Remove liver from milk, and transfer to another bowl. Season with salt and pepper. Place 1/2 teaspoon orange zest and 1 sage leaf in the center of each square. Top each with a piece of liver. Wrap caul fat around liver to enclose, forming little bundles, and set aside.
In a medium saucepan, bring 4 cups of water to a boil. While whisking constantly, add polenta in a thin stream. When all of the polenta is added, season with salt and pepper, cook for 3 minutes.
To a cold nonstick skillet, add 2 tablespoons of oil and half of the liver bundles, top-side down. Cook over high heat until well browned, for 4 to 5 minutes per side. Repeat with remaining 2 tablespoons oil and liver bundles.
Spoon 1/2 cup of polenta onto each center of four warmed dinner plates. Place two or three pieces of liver on top, drizzle with vinaigrette, and garnish with zest and shredded sage.