Cast Iron Cornbread Dressing

Ingredients

• 3 cups (15 ounces) cornmeal
• 2 tablespoons sugar
• 1 teaspoon baking powder
• 1 teaspoon baking soda
• ¾ teaspoon table salt
• 4 tablespoons unsalted butter
• 2½ cups buttermilk
• 2 large eggs
• 6 tablespoons unsalted butter, divided
• 1 pound bulk breakfast sausage
• 3 cups finely chopped onion
• 1½ cups finely chopped celery
• 1¼ teaspoons table salt
• 2 teaspoons minced fresh thyme
• 2 teaspoons minced fresh sage
• ½ teaspoon pepper
• 3 cups chicken broth
• 3 large eggs, lightly beaten