potatoes dauphinoise

Ingredients

• 2 cups swiss cheese, shredded
• 1 1/2 cups parmesan cheese, grated
• 2 tablespoons margarine or butter
• 3/4 cup chopped onion
• 1 - sweet potato, peeled and thinly sliced
• 1 - russet or yukon gold potato, peeled and thinly sliced
• 2 medium sized red skinned potatoes, brushed clean and thinly sliced
• 2 cups half and half
• 4 - egg yolks
• 2 - whole eggs
• 1/2 teaspoon salt
• 1/8 teaspoon white pepper
• 1/8 teaspoon nutmeg