In a bowl combine red onion, cider vinegar, and a pinch salt. Stir 1 lb. 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 parsley, tarragon, thyme, and salt. In a nonstick skillet melt 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, browned side up. Cook 7 to 10 minutes more. Drain onion mixture. Serve on hash browns with plain yogurt and parsley. Sprinkle with pepper.