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Potato Leek Gratin Recipe

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4.1 from 22 reviews

  • Author: Sara
  • Total Time: 1 hour 20 minutes
  • Yield: 4 servings
  • Diet: Vegetarian

Description

This Potato Leek Gratin is a rich and comforting casserole featuring tender leeks simmered in a creamy sauce layered with thinly sliced russet potatoes and a blend of Parmesan and Mexican-style cheeses. Baked to golden perfection with a crunchy panko topping and garnished with fresh green onion, this gratin makes for an elegant yet homey side dish perfect for family dinners or special occasions.

Ingredients

Vegetables and Dairy

  • 3 Tbsp unsalted butter
  • 2 leeks
  • 1½ lb russet potatoes (about 3 potatoes)
  • ½ cup heavy (whipping) cream
  • 1 green onion/scallion (chopped, to garnish)

Cheeses

  • 2 cups Parmigiano-Reggiano or Parmesan cheese (grated)
  • 2 cups Mexican-style shredded cheese

Seasonings and Toppings

  • 1 tsp Diamond Crystal kosher salt
  • ¼ tsp thyme (fresh or dried)
  • ⅛ tsp freshly ground black pepper
  • 1 Tbsp panko (Japanese breadcrumbs)

Instructions

  1. Gather Ingredients: Ensure all ingredients are prepared and measured for easy cooking.
  2. Prepare Leeks: Rinse the leeks thoroughly. Cut in half lengthwise and chop into 1-inch pieces. Rinse again under running water to remove any grit.
  3. Grease Baking Dish: Use a small portion of the butter (about 1 Tbsp) to grease your baking dish to prevent sticking.
  4. Cook Leeks: Heat a large skillet over medium-high heat. Add the remaining butter and melt. Add chopped leeks, cover, and let simmer for 20 minutes, stirring occasionally until soft.
  5. Slice Potatoes: Peel the russet potatoes and slice thinly into ¼-inch pieces. Soak the slices in water to prevent discoloration while the leeks cook.
  6. Make Creamy Leek Sauce: After leeks have softened, stir in thyme, kosher salt, black pepper, and heavy cream. Simmer gently for 5 minutes until the sauce thickens slightly.
  7. Preheat Oven: Set your oven to 400°F (200ºC) to prepare for baking.
  8. Assemble Layers: Depending on your baking dish depth, divide potatoes, leek mixture, and cheeses accordingly (shallow dishes use halves, deeper may use thirds). Layer potatoes first, then leek mixture, followed by cheeses. Repeat for all layers.
  9. Add Toppings: Sprinkle panko breadcrumbs and chopped green onion on top for a crunchy, fresh finish.
  10. Bake Covered: Cover the dish tightly with aluminum foil and bake for 45 minutes. Test doneness by inserting a skewer through the foil; if it passes easily through potatoes, it is ready.
  11. Broil for Color: Remove foil and switch oven to broil. Broil for 2–3 minutes until the top is golden brown.
  12. Rest and Serve: Remove from oven and allow to sit for 15 minutes so the gratin firms up slightly. Serve warm as a delicious side dish.
  13. Storage: Store leftovers in an airtight container in the refrigerator for up to 3 days. Freezing is not recommended as it alters potato texture.

Notes

  • Be sure to wash leeks thoroughly to remove all sand and grit trapped within.
  • Soaking potato slices in water prevents them from browning before cooking.
  • Adjust layers in the baking dish according to its depth for even cooking.
  • Covering the dish while baking locks in moisture; broiling at the end adds a delightful crispy topping.
  • Leftovers keep well refrigerated but texture may degrade upon freezing, so avoid freezing.
  • Prep Time: 30 minutes
  • Cook Time: 50 minutes
  • Category: Side Dish
  • Method: Baking
  • Cuisine: French-inspired

Find it online: https://saraflavors.com/potato-leek-gratin-recipe/