In 10-inch skillet, heat 2 tablespoons of the oil over medium-low heat until hot. Add onions; cook 10 minutes, stirring occasionally, or until onions are slightly golden in color. Add garlic; cook an additional minute. Spread onions and garlic evenly in bottom of pie crust. Arrange vegetables in tight spiral pattern over onion mixture, alternating vegetables. Sprinkle with salt, pepper and thyme. Drizzle with remaining 1 tablespoon of oil. Cover with foil.