Waffled Hash Browns with Rosemary

1 (10 oz.) russet (baking) potato, peeled and shredded
1/2 tsp. fresh rosemary, finely chopped, or 1 tsp. dried rosemary
1/4 tsp. salt
1/2 tsp. freshly ground black pepper
1 tsp. unsalted butter, melted
grated cheese, sour cream or ketchup, for serving

Preheat a waffle iron on medium. Squeeze the shredded potato with a towel until it’s as dry as you can manage. (Excess liquid is the enemy of crispiness; your potatoes will steam if they aren’t dried well.)
In a mixing bowl, combine the shredded potato, rosemary, salt and pepper. With a silicone brush, spread the butter on both sides of the waffle iron. Pile the shredded potatoes into the waffle iron–overstuff the waffle iron a bit–and close the lid. (The pressure of the lid will compress the potatoes and help them emerge as a cohesive, waffled unit.) After 2 minutes, press down a bit on the lid to further compress the potatoes. (Careful: The lid may be hot.) Check the potatoes after 10 minutes. They should be just starting to turn golden brown in places. When the potatoes are golden brown throughout, 1 to 2 minutes more, carefully remove them from the waffle iron. Serve with grated cheese, sour cream or ketchup.