Sage Potatoes au Gratin

Potatoes au Gratin has the ability to make potatoes incredibly flavorful and elegant. The best thing is, they are also so very easy to make! #winning

Forget the peeling and boiling of the potatoes. For this recipe they just need to be sliced thin. The texture of these thin potatoes is so perfect because it allows them to absorb the sage infused cream mixture in which they cook. Sprinkled with generous amount of parmesan cheese, these potatoes will complete your meal.

Instructions on how to make this Sage Potatoes au Gratin:

the ingredients to make my sage potato au gratin dish

In a small sauce pan, heat the heavy cream and the half and half. Then add 4-5 whole sage leaves. Let the mixture come to a simmer and remove it from the heat. Let it sit while you work on the potatoes. In the meantime, the sage will continue to steep into the cream mixture.

Milk mixture infusing with sage for the potatoes au gratin

Tip! Warming the milk and sage, infuses the milk with the amazing aroma of the sage without it being overpowering.

Place a mandolin slicer over a large bowl.

Mandolin slicer on top of a bowl

I prefer to use a mandolin slicer as it makes the job even easier. However, if you do not have one, you can just slice them as thin as you can with your kitchen knife.

Tip! Be very careful handling the mandolin slicer, the blade is very sharp. So, it’s best to use the safety attachment to hold the potatoes in place.

The sides of some graters actually have a long slicer that can be used as well.

Cheese grater for the parmesan for my potatoes gratin

Cut off one end of the potato, and start slicing it using the thinnest slice setting on the mandolin. When you’re done slicing the potato, discard the other end left on the potato.

Once all the potatoes are sliced, it’s time to season them.

All potatoes sliced for the au gratin

Season the potato slices generously with salt and pepper. This is your only opportunity to season them before they bake, so make sure you are not skimping on the seasoning. There is nothing worse than a salt-less potato!

Add the parmesan cheese and mix well. Make sure all slices are coated in the seasonings. You might need to fan out some of the slices if they are stuck together.

Chop the remaining 5 leaves of sage finely and add to the potatoes. Keep mixing them to spread the little bits of sage evenly throughout the potatoes.

Coat the bottom of a baking dish with olive oil and place the potatoes in the baking dish.

Remove the sage leaves from the milk mixture and discard them. Pour the milk over the potatoes.

Pat the potatoes down to make sure they are practically completely covered in the liquid.

Tip! If you are a bit short on the liquid (sometimes it depends on the baking dish you use), just add more half and half directly on the potatoes, it’s not a big deal!

the potato au gratin dish with cream barely covering the potatoes.

It’s important to trust your eyes and your judgement when it comes to cooking. Potatoes absorb liquids like a sponge so be mindful of the amount of milk you add. They are not supposed to be “swimming” in liquid but as long as they are practically covered in it, it will be perfect!

Sprinkle parmesan cheese on top of the potatoes, I am a very generous parmesan sprinkler HA! Why not right? It will add saltiness and that delicious nutty parmesan cheese flavor to the dish.

potatoes sprinkled with cheese

Cover the baking dish with aluminum foil. Make sure it’s tightly presses around the baking dish. I usually add two layers of it.

Tip! Adding two layers of aluminum foil, protects the potatoes from drying out and it prevents steam from escaping, which helps the potatoes cook faster.

Bake the potatoes in a preheated 375° oven for 35 minutes.

Remove the aluminum foil and check to see if the potatoes are cooked all the way through.

Tip! I like to use a fork and just insert it into the potatoes, if it goes in nice and easily, they are done. If they feel hard to poke, cover and bake a little more.

If the potatoes are cooked, remove the foil and bake uncovered until it is nice and golden all over. This will take about 10-15 more minutes.

Tip! Baking uncovered will help reduce any excess liquid as well.

Once the potatoes are baked to golden perfection, remove from the oven and let sit for at least 10 minutes before serving. This step will help them settle and finish absorbing any excess liquid. Plus, it will make them safer to eat as they will be pipping hot!

Sage Potato Gratin ready to serve

Sage Potato au Gratin

Potato au gratin is one of those side dishes that will make everyone at the table so happy! Talk about getting seconds and thirds! This dish is delicious and the best part is it's incredibly easy to make! 
Print Recipe Pin Recipe
CourseSide Dish
CuisineAmerican, French, holiday
Keywordholiday potato side dish, potato recipes, potatoes au gratin
Prep Time20 minutes
Cook Time50 minutes
Resting Time10 minutes


  • mandolin slicer
  • Baking Dish


  • 6-7 large Yellow potatoes washed thoroughly
  • 1 cup Heavy cream
  • 1 cup Half and half plus more if needed
  • 1/2 cup Parmesan cheese plus more for sprinkling
  • 10 leaves Fresh sage
  • Salt and pepper
  • Extra virgin olive oil


  • Add the heavy cream, the half and half and 5 sage leaves to a small saucepan.
  • Bring to a simmer and set aside to allow the sage leaves to steep into the milk mixture.
  • Place a mandolin slicer safely on top of a large bowl.
  • Slice all the potatoes and discard both ends of each potato.
  • Season the potatoes generously with salt and pepper.
  • Add the parmesan cheese and mix well. Make sure all potatoes are coated in the seasonings.
  • Chop the remaining leaves of sage finely. Mix in with the potatoes.
  • Coat the bottom of the baking dish with some olive oil and place the potatoes in the baking dish.
  • Pour the milk on top of the potatoes and pat down to help them get soaked in the liquid.
  • The potatoes should be practically covered in the liquid, if they are not, just add a few splashes of half and half as needed.
  • Sprinkle parmesan cheese generously all over the top of the potatoes.
  • Cover tightly with aluminum foil and bake in a preheated 375° oven for 45 minutes.
  • Uncover and check to see if the potatoes are cooked completely. If they are, remove foil and bake uncovered until goden, about 10-15 minutes.
  • Once the potatoes are done, remove from oven and let sit for at least 10 minutes before serving.

Recipe Video Instructions


Be very careful handling a mandolin slicer. They usually have a safety attachment, use it especially towards the end of each potato to protect your fingers.

31 Replies to “Sage Potatoes au Gratin”

  1. I have been checking out your recipe for au gratin potatoes. Used to make them for my husband, he has been gone for 21 years. I made some recently.
    to accompany my meat loaf. I will try your recipe. I always just used milk. I am in my 80,s and I never knew till today reading your re pie, that the sides on the grater is for slicing potatoes or veggies. My Mum used a grater and I was never ever told by anyone that I could slice potatoes. I have a mandolin, have never used it, it is still in its box. I am going to start asking people if they know what the slicer on the side is for. Mine has three on it. You are never too old to learn, something new every day. I am flabbergasted. Thank You.

    1. I’m glad you discovered that! Isn’t it funny how sometimes we have something in front of us and we never noticed what it was for!
      Using the mandolin slicer I find to be easier though, just be careful as it can be very sharp. Good luck trying out the recipe, can’t wait to hear if you liked it!

  2. I would like to save the recipie for the potatoe augratin. Looks delicious. Can you email me? Thanks

  3. In the recipe calls for 10 sage leafs but you just used 5, what do you do with the other 5 leaves? For decoration?

    1. Hi! Thank you for pointing it out. I just fixed the instructions. You chop the remaining finely and mix in with the potatoes.

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