The original recipe did not specify, but I always use fresh herbs from the garden for this:
HERB HASH BROWNS
In a bowl, combine 1/4 cup finely chopped red onion, 1/2 cup cider vinegar and a pinch of salt. Set aside. Stir one pound shredded new potatoes into a bowl of water, drain. Repeat until water is clear. Place potatoes in a salad spinner; spin until dry. Toss with 1/3 cup chopped parsley, 2 tablespoons chopped tarragon, 1 tablespoon chopped thyme and 1/2 teaspoon salt. In a nonstick skillet, melt 1/4 cup butter over medium heat. Add potato mixture. Using a spatula, press into an even layer. Cook 7 to 10 minutes or until browned. Place a baking sheet over top of skillet; invert potatoes. Slide back into skillet, brown side up. Cook 7 to 10 minutes more. Drain onion mixture. Serve on hash browns with plain yogurt and parsley. Makes 4 servings.