Heat oil in a medium saucepan over medium heat. Saute onions until golden, about 7 minutes.
Stir in garlic, wine, broth, tomato paste, raisins, orange zest, thyme, black pepper and parsley. Simmer, uncovered, for 20 minutes, stirring often. When onions are tender increase the heat to high and cook, stirring constantly, until sauce thickens, about 3 minutes.
