Fall Cast Iron Skillet Chicken Pot Pie

Name: Fall Cast Iron Skillet Chicken Pot Pie
Ingredients: For the crust:; 1 1/4 cups All purpose flour; 1/2 teaspoon Salt; 1/2 cup Unsalted butter, cold, cut into cubes; 1/4 cup Buttermilk, cold; 3 Springs thyme, leaves removed from stems; For the Filling; 1 tablespoon Olive oil; 3 Chicken thighs, chopped into 1/2 inch pieces; 2 White onions; 2 Large carrots; 4 Large garlic cloves; 1 Small bunch kale, center ribs removed, greens chopped; 1/2 teaspoon Kosher salt; 1/4 cup All purpose flour; 1 tablespoon Fresh rosemary; 3 cups Chicken broth; 1 Small to medium delicata squash, seeds removed, cut into ½ inch pieces; 1 Large egg