Sunny's Easy Chicken and Dumplings

INGREDIENTS

• 1 medium onion, chopped
• 2 to 3 cups all-purpose flour, plus
• 5 to 6 fresh thyme sprigs, plus 1 tablespoon chopped leaves
• 2 fresh sage sprigs, plus 1 tablespoon chopped leaves
• 1 stalk celery, trimmed and halved crosswise
• 1 teaspoon whole black peppercorns
• 3 cloves garlic, chopped
• 1 tablespoon 1 tablespoon kosher salt, plus more for seasoning
• 1 whole (5 to 6-pound) chicken, skin on, cut into 8 pieces, including neck
• Small bunch parsley stems, plus 1 tablespoon chopped leaves
• 1/4 cup unsalted butter, plus 1 tablespoon
• Special equipment: Kitchen twine
• 6 cups water
• 6 cups low-sodium chicken stock