How to Make It
Preheat the oven to 400°. In a large skillet, heat 1/4 cup of the olive oil over medium heat. Add the onions and cook slowly until caramelized. Remove to a bowl.
Place the pancetta on a baking sheet and cook in the oven until crisp, 12 to 15 minutes. Transfer to paper towels to drain.
Combine the vinegar, sugar and wine in a 6-quart saucepan and bring to a boil. Add the turnips and cook for 5 minutes, or until tender. Remove the turnips and drain.
In a clean skillet, heat the remaining 1/4 cup of olive oil. Dredge the liver in the seasoned flour, and add half of the slices to the skillet. Cook the liver, undisturbed, over moderately high heat until dark brown, 3 to 4 minutes. Transfer to a platter. Add the balsamic vinegar and caramelized onions to the skillet and bring to a boil, then reduce the heat and simmer for 3 minutes. Return the liver to the skillet and cook for a minute, then add the parsley. Transfer the liver and sauce to a platter, top with the pancetta and turnip halves and serve.