Adjust oven racks to lower middle and upper positions and heat oven to 400 degrees. Coat a 13- by 9-inch pan with olive oil. Working in 4 layers, arrange potatoes in an overlapping single layer; lightly sprinkle with salt and pepper and drizzle with ½ cup of the broth; repeat 3 more times. Cover potatoes with a sheet of parchment and then a sheet of foil; bake on lower-middle rack until tender, about 1 hour. Remove pan from oven and sprinkle with cheese; turn oven to broil. Return pan to upper position and broil until cheese melts and is spotty brown, 2 to 3 minutes longer. Let rest a few minutes and serve.
Recipe by Three Many Cooks at https://threemanycooks.com/recipes/salads-and-sides/rosemary-potato-gratin/