Heat oven to 450°F. Spray cookie sheet with cooking spray.
In 10-inch skillet, heat oil over medium-low heat. Cook onions in oil about 30 minutes, stirring occasionally, until onions are soft and brown.
Unroll pie crust on cookie sheet. Spread onions evenly over crust, leaving about 1 inch around edge. Sprinkle olives on top. Fold crust edge over in 2-inch sections. Continue around whole pie.
Bake 18 to 20 minutes or until crust is golden brown and crisp.
Sprinkle pie with fresh thyme.