Step 1

Arrange a rack in the middle of the oven and heat the oven to 450°F. Line a 9x13-inch baking dish with aluminum foil.

Step 2

Pick the leaves from 4 sprigs of fresh thyme and finely chop (about 1 1/2 teaspoons). Finely grate the zest of 2 large or 3 medium lemons until you have 1 tablespoon. Juice 1 of the lemons until you have 2 tablespoons.

Step 3

Place 4 tablespoons unsalted butter in a large microwave-safe bowl and microwave until melted, 30 to 45 seconds. (Alternatively, melt on the stovetop and transfer to a large bowl.) Add the thyme, half of the lemon zest, 1 tablespoon of the lemon juice, 1 1/2 teaspoons kosher salt, and 1/2 teaspoon coarsely ground black pepper. Stir to combine.

Step 4

Peel 2 pounds russet potatoes. Trim the rounded ends slightly, then cut the potatoes crosswise into 1-inch-thick rounds. Place the potatoes in the butter-herb mixture and toss to coat.

Step 5

Using tongs or your hands, transfer the potatoes to the baking dish, arranging them cut-side up in a single layer. Spoon any remaining butter mixture over the potatoes (about 1 teaspoon per piece).

Step 6

Roast until the potatoes easily release from the bottom when picked up with tongs and the edges are beginning to turn golden-brown, about 15 minutes. Flip the rounds. Return to the oven and roast until the second side is golden-brown, about 15 minutes. Meanwhile, pour the remaining 1 tablespoon lemon juice and 3/4 cup low-sodium vegetable or chicken broth into a liquid measuring cup and stir to combine.

Step 7

Carefully pour the lemon broth into the baking dish. Return to the oven and roast until the potatoes are very tender and most of the broth is absorbed, about 15 minutes. Garnish with the remaining lemon zest and more fresh thyme leaves before serving.