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gratin sweet potatoes

Savory Sweet Potato Gratin Recipe with Gruyere and Parmesan from NYTimes

This sweet potato gratin has everything you need to make a crowd-pleasing dish: a garlicky herb cream sauce, gruyere and parmesan cheese, and thinly sliced sweet potatoes. 

Course Side Dish
Cuisine American
Keyword cream sauce, gratin, gruyere, herbs, holiday dish, parmesan, savory, sweet potato
Prep Time 45 minutes
Cook Time 1 hour 5 minutes
Total Time 1 hour 50 minutes
Servings 12 servings
Calories 247 kcal
Author Emily


  • 3 tbsp butter for greasing pan
  • 1/3 cup Parmesan plus more for sprinkling on top of gratin
  • 2 cups heavy cream
  • 2 tbsp fresh sage chopped
  • 2 tbsp fresh rosemary finely chopped
  • 4 large garlic cloves minced
  • 1/4 teaspoon nutmeg original recipe recommends fresh nutmeg, although I used ground
  • 1 1/2 teaspoons kosher salt plus more to taste
  • 3 eggs, large lightly beaten
  • 3 lbs sweet potatoes about 4 large.
  • freshly ground pepper to taste
  • 1 2/3 cups grated Gruyère cheese around 6 1/2 ounces


  1. Prepare your sweet potatoes by rinsing and peeling.

    sweet potatoes for sweet potato gruyere gratin
  2. Slice your sweet potatoes into 1/8 inch rounds using a mandoline or a sharp knife. You can prepare the sweet potatoes ahead of time as this can be time consuming.

    preparing for sweet potato gruyere gratin
  3. Preheat the oven to 400 degree F and butter two pie dishes. Also butter foil for covering the pan later. Sprinkle parmesan over the bottom of your dish(es).

    sweet potato au gratin gruyere
  4. Combine cream, sage, rosemary, garlic, nutmeg and a pinch of salt in a pan over medium heat. Whisk often until the garlicky cream sauce begins to simmer. Keep stirring for about 10 minutes, until the sauce thickens somewhat.

    sweet potato au gratin gruyere
  5. In a large bowl crack the eggs and beat them just enough to break up the yolks. Slowly add the cream sauce to the eggs, whisking as you combine.  Put your cream sauce, sweet potato slices, and the grated cheese near your baking dishes.

    ingredients for gratin sweet potatoes
  6. Divide 1/3 of the sweet potatoes between the two pie dishes. In one dish assemble the sweet potato slices into a layer over the grated parmesan, each piece somewhat overlapping the last starting on the outside border and moving in towards the center of the dish. Repeat with second pie dish. Sprinkle both with salt and pepper to taste and divide 1/3 of the cream sauce between the two pie dishes. Top with 1/4 C Gruyere cheese on each pie dish.

    sweet potato gratin
  7. Repeat this step with another layer. Add 1/3 of the potatoes between the two dishes, sprinkle with salt and pepper, divide 1/3 of the cream sauce and sprinkle 1/4 C Gruyere cheese on each dish. For the final layer divide the remaining 1/3 of potatoes, salt and pepper, the rest of the egg mixture, but set the remainder of the Gruyere cheese (about 2/3 cup) to the side.  Press down firmly with a spatula to compact the potato mixture. Cover with foil, place in oven and bake for 40 minutes, or until the potatoes are soft enough to easily pierce with a fork. Remove the foil, sprinkle on the rest of the Gruyere cheese and little Parmesan (if you have extra) and cook for an addition 25 to 30 minutes until bubbly and browning. 

    ready to bake gratin sweet potatoes
  8. Let cool for about ten minutes and then serve. 

    sweet potato gratin gruyere
Nutrition Facts
Savory Sweet Potato Gratin Recipe with Gruyere and Parmesan from NYTimes
Amount Per Serving (1 g)
Calories 247 Calories from Fat 169
% Daily Value*
Fat 18.8g29%
Saturated Fat 11.2g70%
Cholesterol 100mg33%
Sodium 254mg11%
Potassium 2471.4mg71%
Carbohydrates 9.9g3%
Fiber 1.4g6%
Sugar 2.7g3%
Protein 10.3g21%
Calcium 284mg28%
Iron 2mg11%
* Percent Daily Values are based on a 2000 calorie diet.