Reduced-Fat Scalloped Potatoes | America's Test Kitchen

Ingredients

• 2 1/2 pounds Yukon Gold potatoes , peeled and sliced 1/8 inch thick
• 1 1/2 cups 2 percent low-fat milk
• 1 tablespoon unsalted butter
• 1 large onion , chopped fine
• 1 garlic clove , minced
• 1 cup low-sodium chicken broth
• 1 tablespoon cornstarch
• 1 tablespoon all-purpose flour
• 1 teaspoon salt
• 1/2 teaspoon pepper
• 2 ounces extra-sharp cheddar cheese , shredded (1/2 cup)
• 1 ounce Parmesan cheese , grated (1/2 cup)
• 2 tablespoons panko bread crumbs