1Heat oil in 12-inch skillet over medium-high heat. Sprinkle both sides of turkey with salt and 1/4 teaspoon pepper. Cook turkey in oil about 5 minutes, turning once, until brown on both sides.
2Pour wine into skillet; reduce heat. Cover and simmer 30 to 40 minutes or until juice of turkey is no longer pink when centers of thickest pieces are cut. Remove turkey from skillet; keep warm.
3Melt butter in skillet over medium-high heat. Cook onions in butter 5 minutes, stirring frequently; reduce heat to medium. Stir in brown sugar, thyme and 1/4 teaspoon pepper. Cook 15 to 20 minutes, stirring occasionally, until onions are golden brown.
4Slice turkey. Serve turkey with onions.