Heat your oven to 425 degrees and pull the turkey thighs out of the refrigerator about 20 minutes before cooking so they are not ice cold when they go in. Pat each thigh completely dry with paper towels. Dry skin is the key to getting it crispy rather than steamed.

In a small bowl, mix together the smoked paprika, garlic powder, 1 teaspoon of the kosher salt, and the black pepper. Drizzle 1 tablespoon of olive oil over the turkey thighs and rub the spice mixture all over them, getting under the skin at the top where you can reach without tearing it.

Add the cubed potatoes, parsnips, onion wedges, and smashed garlic cloves to a large bowl. Drizzle with the remaining 2 tablespoons of olive oil, sprinkle with the remaining 1/2 teaspoon salt and the dried thyme, and toss to coat everything evenly.

Spread the vegetables in a single layer on the sheet pan. Do not pile them up or they will steam instead of roast. Set the turkey thighs directly on top of the vegetables, skin side up. The thighs will sit slightly elevated, and their drippings will baste the vegetables below as everything cooks.

Roast on the center rack for 45 to 50 minutes. The skin should be deep reddish-brown and the potatoes should be fork-tender. Check the internal temperature of the thickest thigh with a meat thermometer. You want 175 degrees for dark meat, which stays juicy at that temperature rather than drying out.

Let the turkey thighs rest directly on the pan for 5 to 8 minutes before serving. This lets the juices redistribute back into the meat. Serve the thighs over the vegetables and spoon any pan drippings over the top.