The best part of this showstopping dish is the caramelized edges.
Preheat oven to 400°F. Place squash, cut side down, in an 8-inch square baking dish; fill with 1 inch of water. Cover with plastic wrap, and microwave on HIGH 5 minutes. Thinly slice squash, and place in a large bowl.
Heat a 10-inch cast-iron skillet over medium. Cook bacon 5 minutes. Increase heat to medium-high, and cook until golden brown. Remove bacon, reserving drippings in skillet. Crumble bacon, and set aside. Reduce heat to medium; add onion to skillet, and cook until translucent, about 2 minutes. Stir in oil, thyme, salt, pepper, and 2 teaspoons of the maple syrup. Add mixture to squash slices; toss to combine.
Starting at the outer edge of the same skillet, arrange squash slices in slightly overlapping concentric circles to form a flower shape. Bake in preheated oven until squash is tender and edges begin to crisp, about 40 minutes. Drizzle with remaining 2 teaspoons maple syrup. Top with bacon.