Loaded Baked Potato Casserole - Master recipes

Ingredients

• 2 pounds potatoes, peeled and thinly sliced (about 6 cups) -
• 1 large onion, halved and thinly sliced -
• 1/4 cup water -
• 1/4 cup butter, cubed -
• 1/3 cup all-purpose flour -
• 1 teaspoon salt -
• 1 teaspoon ground mustard -
• 1/2 teaspoon pepper -
• 2 cups 2% milk -
• 4 cups shredded cheddar cheese, divided -
• 4 cups fresh small broccoli florets -
• 3 cups cubed fully cooked ham -
• 2 tablespoons minced fresh chives -