Ingredients:

  • 2.5 lbs Yukon Gold potatoes, thinly sliced
  • 1 medium yellow onion, thinly sliced
  • 2 cloves garlic, minced
  • 4 tablespoons unsalted butter, melted
  • 3 tablespoons all-purpose flour
  • 2 cups whole milk
  • 1 cup heavy cream
  • 1 cup shredded Gruyère cheese, plus more for topping (optional)
  • 1/2 teaspoon ground nutmeg
  • 1 teaspoon salt, or to taste
  • 1/2 teaspoon black pepper, or to taste
  • 2 tablespoons chopped fresh parsley, for garnish (optional)
  • Cooking spray

Instructions:

  1. Wash and thinly slice the potatoes and onion.
  2. Melt butter in a saucepan over medium heat. Add garlic and cook until fragrant. Whisk in flour to form a roux.
  3. Gradually whisk in milk and cream until smooth. Simmer until thickened. Stir in Gruyère cheese, nutmeg, salt, and pepper.
  4. Grease the slow cooker. Layer potatoes, onions, and cheese sauce in the slow cooker, repeating layers until all ingredients are used, ending with sauce.
  5. Cover and cook on low for 4-6 hours, or on high for 2-3 hours, or until potatoes are tender.
  6. Sprinkle with extra Gruyère (if using) and broil for a few minutes until golden brown and bubbly (watch carefully!).
  7. Let stand for 10 minutes before serving. Garnish with fresh parsley.