Holiday Dressing Muffins - Alton Brown

Ingredients

• 20 ounces bread-ciabatta, French bread, or a mixture, torn into 1-inch pieces
• 1 stick room temperature unsalted butter, divided
• 8 ounces bulk breakfast sausage
• 2 1/2 cups chopped yellow onion
• 2 1/2 cups chopped celery
• 1 1/2 teaspoons kosher salt
• 1 teaspoon rubbed sage
• 1/4 teaspoon dried thyme
• 1 1/2 teaspoons freshly ground black pepper
• 1/2 teaspoon dry mustard (we like Coleman's)
• 2 teaspoons minced fresh rosemary
• 1 1/4 cups chopped fresh parsley
• 1/4 cup chopped celery leaves
• 4 large eggs, beaten
• 2 1/2 cups chicken stock