Prepare and bake piecrust in a 9-inch pie plate according to package directions.
Heat olive oil in a skillet; add onion, and cook 15 minutes or until tender. Stir in salt and pepper.
Spread onion over bottom of crust, and top with basil and 1 cup goat cheese. Arrange tomatoes over cheese. Top with olives. Sprinkle with remaining cheese. Bake at 375° for 8 to 10 minutes or until cheese starts to brown slightly. Garnish, if desired.