Preheat your oven to 400°F, positioning the rack in the lower-middle section.
In a bowl, combine halved red potatoes, onion wedges, and whole garlic cloves. Drizzle with olive oil, then season generously with dried thyme, kosher salt, and freshly ground black pepper. Toss thoroughly to coat every surface. Arrange potatoes cut-side down.
Roast for 45–50 minutes, flipping or shaking every 15 minutes to promote even browning. The potatoes are done when their edges are crisp, interiors tender, and onions caramelized. A final sprinkle of salt enhances flavor just before serving.
