Grandma's Famous Potatoes Au Gratin Recipe

Ingredients

• 3 tablespoons grated parmesan cheese
• 1/2 teaspoon freshly cracked black pepper
• 1 1/2 teaspoons kosher salt
• 3 lbs yukon gold potatoes, peeled and sliced thin
• 1 yellow onion, sliced into thin rings
• 3 cups shredded sharp cheddar cheese
• 1 cup heavy cream
• 3/4 cup strong chicken broth
• 1/4 cup dry white wine
• 1 teaspoon rubbed sage
• 1/2 teaspoon prepared horseradish or 1/2 teaspoon dry mustard
• 1 dash ground nutmeg
• 2 tablespoons powdered parmesan cheese
• 1 dash paprika
• parsley flakes