Heat 3 tablespoons of the oil in a large saucepan and cook the onions, covered, over low heat, until softened, about 30 minutes, stirring frequently. Heat the remaining oil in a frying pan and brown the rabbit pieces, over a moderate heat, turning frequently. Place the rabbit pieces in the saucepan with the onions. Season with salt and pepper. Pour in the white wine and bring to a boil. Reduce heat to a simmer, cover, and cook gently for 20-25 minutes longer.
