1. Preheat oven to 475 degrees. Place a rimmed baking sheet on the upper and lower third racks.

2. In a large bowl, combine pumpkin, red onion, apple, turnips, and thyme. Add olive oil and season with coarse salt and pepper; toss to combine.

3. Remove hot baking sheets from oven and divide vegetable and fruit mixture evenly between them, spreading in an even layer. Return baking sheets to oven and roast, stirring occasionally, until golden brown and tender, about 35 minutes, rotating baking sheets from top to bottom halfway through baking.

4. Remove baking sheets from oven and drizzle with vinegar; shake to combine. Transfer to a serving platter; drizzle with olive oil and garnish with thyme leaves. Season with sea salt and serve.