Skillet of Sweet Potato Parmesan Gratin with a slice removed
4.45 from 9 votes

Sweet Potato Parmesan Gratin

A simple gratin featuring sweet potatoes, thyme, low-fat milk, and parmesan cheese. Healthier than your average gratin yet just as satisfying.
Author: Minimalist Baker
Prep Time 10 minutes
Cook Time 1 hour 15 minutes
Total Time 1 hour 25 minutes
Servings: 6
Category: Side
Cuisine: Gluten-Free, Vegetarian
Freezer Friendly No
Does it keep? 2-3 Days


  • 2 organic sweet potatoes (sliced in thin rounds)
  • 1 small red or yellow potato
  • ~1/4 tsp each salt and freshly ground pepper
  • 1 tsp thyme (roughly chopped // fresh or dried)
  • 3/4-1 cup Parmesan cheese (finely grated*)
  • 2 cups low-fat milk (I used 2%)*


  1. Preheat the oven to 400 degrees F (204 C).
  2. Butter or lightly oil a baking dish or cast iron skillet.
  3. Place the sliced potatoes in a bowl and season generously with salt and pepper. Add the thyme and half of the cheese and toss together.
  4. Transfer to the dish and pour on the milk. It should just cover the potatoes.
  5. Bake 30 minutes, remove from oven and carefully drain off a bit of the liquid (about 1/3 cup as original recipe is written). Sprinkle the remaining cheese over the top and return to the oven.

  6. Bake another 45-50 minutes, until the milk is absorbed, the potatoes are soft and the top and edges are golden. (Optional: drain off a bit more of the liquid as using low-fat milk instead cream can result in a bit of wateriness.)

  7. Let rest at least 20 minutes before serving so the juices can redistribute.
  8. Can be made ahead of time and reheated in the microwave or oven for serving.


*You can substitute other cheeses besides parmesan, such as gouda or asiago.
*You can use cream or half and half instead of low-fat milk, but it will add a lot more fat and calories overall.
*Nutrition information is a rough estimate.

Nutrition Per Serving (1 of 6)