This version of the classic side uses thawed frozen hash browns to start.
In an 8-inch nonstick skillet, melt 2 1/2 teaspoons butter over medium-high. Add hash browns and press evenly into skillet with a rubber spatula. Season with salt and pepper. Cook, pressing on potatoes and tucking in edge occasionally with spatula, until crisp and deep golden brown, 10 to 15 minutes. (Adjust heat if necessary to prevent cake from over-browning.) Flip pancake and repeat, adding 2 1/2 teaspoons butter to skillet. To serve, cut pancake into quarters.