Potato Leek Gratin with Fennel

Baked potato gratin with crispy edges sprinkled with parmesan cheese.

5 from 11 votes

This creamy Potato Leek Gratin loaded with gruyere and parmesan cheese will bring smiling faces to the dinner table! Perfectly browned with crispy edges and rich, tender scalloped potatoes. An indulgent side that’ll have your gang asking for more!

Course Side Dish

Cuisine American, Gluten Free, Vegetarian

Diet Gluten Free

Prep Time 20

Cook Time 1 10

Total Time 1 30

Servings servings

Calories 337kcal

Author Kim Peterson

Equipment

Ingredients

2 tablespoons butter
3 leeks , white and pale green parts only sliced into ¼-inch half moons
4 cloves garlic , minced
2 fennel bulbs with fronds , trimmed, cored, thinly sliced, 2 tablespoons fronds reserved
¼ cup fresh parsley , chopped
3 pounds red-skinned or yukon gold potatoes , peeled, cut into ¼-inch thick slices
2 cups gruyere cheese , shredded
1 ½ cups Parmesan cheese , freshly grated
1 cup whole milk
1 cup heavy cream

Instructions

Preheat oven to 375°F. Butter 13x9x2-inch baking dish.
Melt 2 tablespoons butter or olive oil in large skillet over medium heat. Add leeks and cook until tender, stirring occasionally, about 7 minutes.
Add garlic and cook 1 minute, stirring frequently. Remove from heat.
Arrange half of sliced fennel in a even layer in prepared baking dish. Sprinkle with 1 tablespoon fennel fronds, half of the parsley, and season with salt and pepper.
Arrange half of sliced potatoes overlapping slightly on top of the fennel and herbs. Top potatoes with half of leek mixture. Sprinkle generously with salt and pepper. Spread half of gruyere and grated parmesan cheese over.
Repeat layering with remaining fennel, herbs, potatoes, leek mixture, and cheeses. Sprinkle assembled gratin with salt and pepper.
Bring whole milk and heavy cream to a simmer in a small saucepan. Pour mixture over gratin.
Bake uncovered until vegetables are very tender, liquid is almost absorbed and top is deep golden brown, about 1 hour to 1 hour 10 minutes.
Let gratin rest 10 minutes before serving. Garnish with extra fennel fronds and parsley. Enjoy!

Notes

Recipe Tips

Prepping Leeks – Use white and light green parts only Halve lengthwise and rinse to remove any hiding grit between the layers.
Slicing Potatoes – A handheld mandoline is an economical gadget that makes uniform slicing a breeze, or use a sharp knife.
Seasoning - Be sure to season each layer of potatoes with kosher salt and ground black pepper to maximize flavor.
Sauce - Stick with whole milk and heavy cream to minimize the risk of the sauce breaking.
If halving the recipe, use an 8x8 or 9x9 casserole dish.

To Make Ahead

Can be prepared 3 hours ahead. Let stand at room temperature covered in foil. Rewarm covered in 375°F oven 20-30 minutes. You can also prepare and bake the gratin 1 day ahead. Cover and refrigerate. Bring to room temperature and bake as just mentioned until hot. Leftovers keep in the fridge for 4 to 5 days.

To Freeze

Let gratin cool completely after baking. Cut into individual portions or leave uncut in casserole dish. Either way, wrap tightly with foil and freeze up to 3 months. When ready, thaw in the refrigerator overnight or bake from frozen. Bake covered with foil at 375 degrees F until potatoes are hot and golden, 45 to 60 minutes. Double the time if potatoes are frozen.

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