Overnight Croissant Ham and Cheese Breakfast Casserole

Bahan-bahan (8 porsi)

• 4 large croissants ((6+ cups chopped))
• ¾ cup shredded Swiss cheese
• 1½ cups diced ham
• ⅓ cup finely chopped sweet onion
• 9 large eggs
• 1 cup whole milk
• ¾ cup sour cream
• 2 tablespoons Dijon mustard
• ¼ teaspoon salt
• ¼ teaspoon freshly ground black pepper
• ½ cup shredded cheddar cheese
• ¼ cup chopped green onions