easy weeknight chicken and dumplings

For soup:

• 2 tbsp. olive oil
• 1 1/2 lb. boneless, skinless chicken thighs
• Kosher salt and freshly ground black pepper
• 1 medium yellow onion, chopped
• 2 carrots, chopped
• 2 celery stalks, chopped
• 2 bay leaves
• 1 sprig thyme
• 1 (8-ounce) package sliced mushrooms
• 3 tbsp. all-purpose flour
• 2 (32-ounce) containers chicken stock

For dumplings:

• 1 1/2 c. all-purpose flour, spooned and leveled
• 1 1/2 tsp. baking powder
• 1 tbsp. fresh thyme
• 1 tsp. kosher salt
• 3/4 c. buttermilk
• 1 large egg

1. Make soup: Heat oil in a large Dutch or pot oven over medium-high heat. Season chicken with salt and pepper. Cook, in batches, turning once, until brown and just cooked through, 8 to 10 minutes. Transfer to a plate and shred with two forks; reserve pot. 
2. Reduce heat to medium. Add onion, carrots, celery, bay leaves, and thyme sprig to reserved pot. Season with salt and pepper. Cook, stirring occasionally, until starting to soften, 4 to 6 minutes. Add mushrooms and season with salt and pepper. Cook, stirring occasionally, until mushrooms are starting to soften, 2 to 4 minutes. Add flour and cook, stirring, 30 seconds. Add stock and chicken. Bring to a boil. Reduce and simmer until starting to thicken slightly, 6 to 8 minutes. 
3. Make dumplings: Meanwhile, combine flour, baking powder, thyme, and salt in a bowl. In a measuring cup whisk together buttermilk and egg. Add wet ingredients to dry ingredients and stir to combine. 
4. Drop 6 large mounds of mixture on top of soup. Cover and simmer until dumplings are cooked through, 15 to 20 minutes. Discard bay leaves and thyme. Serve immediately.