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+ servings
A sweet potato casserole

Sweet Potato Gratin with Gruyère & Prosciutto

A rich, cheesy, sweet potato gratin with sage and thyme is sweet, savory & perfect for Thanksgiving.
Course Dinner, Holidays
Cuisine International
Prep Time 20 minutes
Cook Time 1 hour 10 minutes
Servings 8
Calories 443kcal
Author by Jenny Skrapaliori Graves


  • 6 medium sweet potatoes Sliced into ⅛-inch-thick rounds.
  • 3 tbsp butter softened
  • 1.5 cups grated Gruyère cheese
  • 4 oz prosciutto cubetti
  • 2 cups heavy cream
  • 3 tbsp fresh sage chopped
  • 1 tsp ground nutmeg
  • 1 tbsp fresh thyme leaves
  • 3-4 cloves
  • 4 garlic cloves minced
  • 3 eggs lightly beaten
  • salt
  • freshly ground pepper


  • Heat oven to 400 degrees.
  • In a medium pot, bring cream, a few sage leaves, cloves, a couple of thyme sprigs, minced garlic, ground nutmeg, and a pinch of salt to a simmer.
    Simmer until reduced a little, about 10 minutes.
    When the cream mixture is ready pour it thru a sieve to strain herb sprigs and cloves.
  • In a large bowl, lightly whisk the eggs.
    Slowly pour the cream into the eggs; keep whisking while pouring. Mix well. Set aside.
  • Butter a 10.5" X 7.5" baking pan or gratin dish.
    Sprinkle grated cheese all over the bottom of your pan.
  • Place a layer of potatoes in the pan, slightly overlapping as you go.
    Sprinkle a pinch of salt and freshly ground pepper over sweet potatoes.
    Pour ⅓ of the egg mixture—top potatoes with ½ cup Gruyère and 1 tablespoon of prosciutto.
  • Repeat with another layer of potatoes, a small pinch of salt and freshly ground pepper and ⅓ egg mixture. Top again with ½ cup Gruyère and 1 tablespoons of prosciutto.
  • Top with the last layer of potatoes, a small pinch of salt and fresh ground pepper, and the remaining egg mixture. Top again with ½ cup Gruyère and 1 tablespoon of prosciutto cubetti.
    Cover with a buttered foil sheet and bake until potatoes are tender, about 40 minutes.
  • Remove foil, sprinkle top with remaining grated Gruyère.
    Bake until nicely browned and bubbling for 25-30 minutes.
    Let au-gratin cool a little and serve.


Nutritional Info – Please keep in mind that nutritional information provided is only an estimate and can vary based on products used.


Calories: 443kcal | Carbohydrates: 15g | Protein: 13g | Fat: 37g | Saturated Fat: 22g | Cholesterol: 185mg | Sodium: 263mg | Potassium: 304mg | Fiber: 2g | Sugar: 3g | Vitamin A: 9425IU | Vitamin C: 4mg | Calcium: 384mg | Iron: 1mg