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4.72 from 7 votes

Cajun Potatoes Au Gratin

Course Side Dish
Cuisine Canadian
Keyword cheesy potatoes, potatoes au gratin
Prep Time 15 minutes
Cook Time 1 hour 20 minutes
resting time 30 minutes
Total Time 1 hour
Servings 10
Calories 535kcal
Author Julie & Debbie


  • 7 large potatoes Yukon Gold or Russets
  • 4 tbsp butter
  • 4 tbsp flour (or you can use cornstarch 3 tbsp or so)
  • 1 large onion sliced
  • 3 cloves garlic minced
  • 1 tbsp fresh thyme or dried
  • 2 cups chicken broth you can use veggie broth too
  • 1 cup heavy cream
  • 1 cup half and half cream
  • 2 cups gruyere cheese grated and divided in half
  • 2 cups cheddar cheese grated and divided in half
  • 2 tbsp cajun seasoning (you can use more or less of this depending on how spicy you like things)
  • 1 tsp salt or to taste but don't add more if your cajun spice has a lot of salt
  • 1/2 cup fresh chives


  • Wash your potatoes well and slice them using the mandolin. Not too thin. Slice the onions on the mandolin too if you like. If you don't have a mandolin, slice them with a sharp knife. Layer the potatoes and onions in an oven proof dish and set aside.
  • Preheat oven to 400 degrees.
  • Make a roux. In a medium pot, melt the butter over medium heat and add the minced garlic and thyme. Cook for a couple mins. Add the flour to the mix and cook for a couple mins, stirring with a whisk.
  • Slowly add the chicken broth, heavy cream and light cream to the roux while you whisk. Cook until the sauce coats the back of a spoon well. Remove from the heat.
  • Add 1 cup of each kind of cheese bit by bit and stir till its all melted.
  • Add the cajun seasoning and then the salt after you taste it. Some cajun seasoning has a lot of salt in it so you want to be careful not to add too much.
  • Pour the lot over the potatoes and shake the pan violently and bang it around so that the sauce gets down in between all the cracks in the potatoes. Spread the rest of the cheese all over the potatoes and then sprinkle the chives too. Cover the dish with foil or a lid.
  • Cook with the foil on for 30 mins and then take the foil off for the last 15 - 20 mins so that the Cheese gets all brown and yummy. They are ready when a knife slips easily into the center of the dish.


Tips on How to Make a Cheese Sauce Perfectly

  • use some high fat liquid! If you are trying to lighten up the sauce its tempting to use skim milk or coconut milk, but if you do, your sauce will almost always separate and you end up with pools of oily fat. Use at least some heavy cream in your dish.
  • if the sauce does separate, try adding some cold heavy cream and whisk. It might come back together.
  • never let your sauce boil, if the temperature gets too high, it can cause the sauce to curdle or split.
  • always remove the sauce from the heat before adding the cheese

Tips for Baking your Potatoes Au Gratin

  • bake covered for at least half the baking time. Use tin foil if you have to, but it will cut your baking time down.
  • always put a baking tray underneath your potatoes au gratin dish! Its common for the sauce to bubble out of the dish and you don't want it all over your oven.


Serving: 1tenth of the recipe | Calories: 535kcal | Carbohydrates: 40g | Protein: 23g | Fat: 33g | Saturated Fat: 20g | Fiber: 7g | Sugar: 1g