INSTRUCTIONS
1. Adjust rack to middle position and place an empty 132. by 9-inch baking dish in the middle. Preheat the oven to 425°F.
3. In a large bowl, toss fennel, onions, 1 tablespoon of olive oil, and salt and pepper to taste. When the oven is hot, remove the baking dish, add the vegetables, and return to oven. Roast, stirring occasionally, until starting to tenderize, about 30 minutes.
4. Meanwhile, drizzle 2 teaspoons of olive oil over pork and season with salt and pepper. Rub fennel seeds and thyme leaves on exterior. When vegetables are ready, remove baking dish from oven, and push the vegetables to the sides of the dish with a spatula or wooden spoon. Place the pork in the center and return to oven. Roast until the thickest part of the pork registers 145°F on an instant-read thermometer. Remove from oven and allow to rest for 10 minutes.
5. While the pork is resting, whisk together remaining 2 tablespoons of olive oil and 1 tablespoon of balsamic vinegar. Slice the pork into thick rounds, and plate along with the roasted fennel and onion. Drizzle the olive oil and vinegar over the top. Serve immediately.
