2/3 cup whole milk
1 large egg, lightly beaten
1 tbsp. cold butter
1/2 tsp. salt
1 tbsp. baking powder
2 cups all-purpose flour
1 cup apple cider or juice
3 cups chicken broth
3 tbsp. all-purpose flour
Salt and pepper to taste
2 tbsp. minced fresh parsley
1 celery rib, chopped
1 medium red onion, chopped
2 tbsp. butter
8 bone-in chicken thighs (3 pounds), skin removed