– 3 tablespoons unsalted butter
– 1 small yellow onion , peeled and diced
– 3 garlic cloves , minced
– 3 tablespoons all-purpose flour
– 1 cup heavy cream
– 1 cup milk
– ½ cup chicken broth
– 2 teaspoons salt , plus additional to taste
– ¼ teaspoon black pepper , plus additional to taste
– 3 lb yellow potatoes , thinly sliced (peeled or unpeeled)
– ½ cup grated Parmesan