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Potato Leek Casserole - ultimate comfort food side dish that resembles in taste famous Potato Leek Soup; topped with cream and Gruyer Cheese, rich, decadent, elegant and delicious casserole- Innocent Delight

Potato Leek Casserole

Course: Casserole, Potato
Cuisine: French
Prep Time: 25 minutes
Cook Time: 50 minutes
Total Time: 1 hour 15 minutes
Servings: 8
Calories: 471kcal
Author: Edyta
This side dish is made based on Julia Child's Potato Dauphinois Gratin but has a twist of the addition of sautéed leeks and resembles in taste the famous Potato Leek Soup; This casserole is full of flavor with garlic, cream, Gruyere cheese, and thyme. It's rich, decadent and elegant at the same time. It can be served as a perfect side dish for any Holidays or other gatherings.
Print Recipe


  • 2 pounds of Russet Potatoes (See note 1), peeled and cut into 1/8 inch slices
  • 2 leeks , trimmed, washed and chopped
  • 1 garlic clove , cut in half
  • 4 tablespoon of butter
  • 2 cups of Gruyere Cheese (or Cheddar - See note 2)
  • 2 cups of heavy cream
  • 2 teaspoon of fresh thyme
  • Salt and Pepper to taste


  • Trim and cut the leeks in half inches squares (cut the leeks lengthwise twice, first in half, then in quarters and then chop);
  • Place the leeks in a bowl of water to remove all the sand;
  • Scoop them out with a slotted spoon from the top and place on the paper towel to remove extra water;
  • In a skillet melt 2 tablespoons of butter;
  • Add leeks and sauté them until soft, stirring often for about 10 minutes;
  • Add cream, salt, and pepper and let the cream cook with leeks for about 3-4 minutes until the mixture thickens slightly, set aside
  • Using either mandolin or sharp small knife cut the potatoes in 1/8 inch slices;
  • Rub the garlic all over either the cast iron skillet or casserole dish and smear with 2 tablespoon of butter (9 inches round or 8x8 inches square);
  • Spread the first layer of potatoes at the bottom of the dish;
  • Add 1/3 of the cream-leek mixture;
  • Sprinkle with salt, pepper, 1/2 cup of cheese and 1/3 of thyme;
  • Repeat the process with two more layers and use all the remaining cheese on top;
  • Cover the dish with foil and bake for about 40 minutes in preheated oven to 350 F;
  • Then remove the foil and bake it for another 10 minutes until the cheese is golden and bubbly.


1. I used yellow potatoes, but Russet will work great as you need starchy potatoes
2. If you cannot find Gruyere or you don't want to use it as it is pretty pricey, you may substitute with Cheddar or other well-melting cheese.


Calories: 471kcal | Carbohydrates: 19g | Protein: 14g | Fat: 38g | Saturated Fat: 23g | Cholesterol: 132mg | Sodium: 199mg | Potassium: 579mg | Fiber: 3g | Sugar: 1g | Vitamin A: 1735IU | Vitamin C: 16.1mg | Calcium: 421mg | Iron: 4.2mg