1. Pound chicken breasts to half-inch thickness.
2. Heat oil in a large nonstick skillet over medium-high heat. Sprinkle chicken with one-fourth teaspoon salt and pepper and add to pan. Cook three minutes on each side or until done. Transfer chicken to a serving platter; keep warm.
3. Add onions and mushrooms to pan; sauté for four minutes or until browned, stirring occasionally. Add garlic; sauté for one minute, stirring constantly. Stir in wine, scraping pan to loosen browned bits.
4. Bring to a boil, and cook until liquid almost evaporates. Sprinkle mushroom mixture with remaining one-fourth teaspoon salt and potato starch; cook for 30 seconds, stirring frequently.
5. Add soup to pan; bring to a boil. Cook two minutes or until slightly thickened. Remove pan from heat; add oil or margarine and thyme, stirring until incorporated.
6. Serve over chicken.