Preheat your oven to 450°F (230°C) and position a rack in the upper third. Use a metal baking pan, not glass, because glass can shatter when the cold broth hits it later.

Peel the 4 pounds potatoes, trim the ends flat, and cut them crosswise into 1 inch thick rounds. Even thickness matters here so they cook at the same rate.

In a large bowl, toss the potato rounds with the ½ cup melted butter, 1½ tablespoons thyme, 1¼ teaspoons salt, and ¾ teaspoon black pepper until every piece is coated.

Arrange the potatoes in a single layer in one or two metal baking pans. Crowding them means they steam instead of brown, so give them room.

Roast for 15 minutes, until the bottoms are starting to brown around the edges.

Pull the pans out and flip each potato with a metal spatula. Roast for another 15 minutes, until browned on the second side.

Flip the potatoes once more, then pour the 2 cups chicken broth around them and scatter in the 4 cloves crushed garlic. Roast for a final 15 to 20 minutes, until the potatoes are fork tender and the broth has reduced into a glossy sauce.

Spoon the pan sauce over the potatoes and serve hot.