Potato Leek Gratin with Crispy Breadcrumbs
This creamy, cheesy Potato Leek Gratin is topped with crispy, buttery breadcrumbs before being baked to tender perfection. The best holiday side dish!
- Prep Time: 20 minutes
- Cook Time: 1 hour 30 minutes
- Total Time: 1 hour 50 minutes
- Yield: 6–8 servings 1x
Ingredients
Units
Scale
- 3 tablespoons butter, divided
- 2 medium leeks, white and light green parts only, halved lengthwise and sliced into half-moons
- 1 1/4 pound Yukon gold potatoes, peeled if desired, sliced into 1/8-inch-thick rounds
- 1 large clove garlic, minced
- 1/4 teaspoon dried thyme
- Pinch of ground nutmeg
- 1 cup heavy cream
- 6 ounces Gruyère cheese, shredded
- 3 ounces Parmesan cheese, shredded
- 1 teaspoon kosher salt
- 1/2 teaspoon freshly ground black pepper
- 1/2 cup Panko breadcrumbs
- Finely chopped chives, for topping
Instructions
- Use one tablespoon of butter to generously grease a 3-quart casserole dish. Preheat oven to 350°F.
- Cook the leeks and aromatics: Melt one tablespoon of butter in a medium saucepan over medium heat. Add the leeks and sauté for 5–7 minutes, or until soft and translucent. Add the garlic, thyme and nutmeg and sauté for another 30 seconds, or until fragrant.
- Finish the cream sauce: Add the cream, salt and pepper and stir to combine. Cook, stirring frequently, until thickened, about 3–4 minutes. Remove from heat and set aside.
- Build the gratin: Layer one third of the sliced potatoes in the buttered baking dish, shingling them so they overlap slightly and cover the bottom of the dish. Pour over one third of the leek and cream mixture and spread it around to coat the potatoes evenly. Sprinkle over one third of the shredded cheeses. Repeat this three times, layering potatoes, cream and cheese, until the dish is full.
- Make breadcrumb topping: Place the remaining tablespoon of butter in a small, microwave-safe bowl. Microwave for about 30 seconds, or until melted. Stir in the breadcrumbs and season with a generous pinch of salt and pepper. Sprinkle the breadcrumbs evenly over the top of the gratin.
- First bake: Cover with foil and bake, covered, for 30 minutes.
- Second bake: Remove the foil, then return to the oven and bake for an additional 45 minutes uncovered. Top with chopped chives and let cool slightly before serving.