Skinny Potato and Fennel Gratin

A serving of skinny potato gratin on a small plate, with the remaining gratin in the background.

5 from 10 votes

A skinny version of a potato gratin, using low-fat milk and vegetable broth to replace heavy cream. And some of the potatoes are replaced with slices of a fennel bulb.

Prep Time30

Cook Time45

Total Time1 15

Course: Vegetable Side

Cuisine: American

Keyword: lightened potato gratin, skinny potato gratin

Servings:

Calories: 222.1kcal

Author: Susan Pridmore

Equipment

Chef's knife
Medium skillet
hand held mandolin
box grater
9" X 9" baking dish
Small skillet
Whisk
Aluminum foil

Ingredients

2 ½ large russet potatoes
2 bulbs fennel
¼ cup grated Gruyere cheese
¼ cup grated Parmesan cheese
1 cup Leek Confit or 2 cups diced yellow onions
1 teaspoon dried rosemary or 2 tablespoons fresh rosemary
1 teaspoon fresh thyme leaves or 2 tablespoons fresh thyme
1 teaspoon kosher salt to taste
¾ teaspoon freshly ground pepper to taste
2 tablespoons unsalted butter
3 tablespoons all-purpose flour
2 cups vegetable broth
⅓ cup low-fat milk

Instructions

Preheat the oven to 400 degrees F.
If using sautéed onions in place of the leek confit, sauté them in 1 tablespoon of olive oil or unsalted butter until softened.
Thinly slice the potatoes and fennel using either a sharp chef's knife or a small hand-held mandolin. I use the second thinnest setting on my mandolin, creating slices that are an even thickness, and only ⅛" thick.
The thicker the slices, the longer it will take for the gratin to cook.
Combine the potatoes, fennel, leek confit (or cooked onions), two-thirds of the grated cheeses, thyme, rosemary, salt and pepper in a large bowl. Gently toss, and transfer to a baking dish.
(The remaining grated cheese will be added to the gratin when it's almost completely cooked.)
In a small skillet over medium heat, melt the butter. When the butter is melted and sizzling, whisk in the flour, one tablespoon at a time.
Cook for a 2 - 3 minutes, occasionally whisking, to cook the flour.
Combine the vegetable broth and milk together in a measuring cup, and slowly whisk it into the flour/butter mixture starting with about two tablespoons at a time.
It will start as a paste, but as you add the broth, it will become a roux sauce. Once a thick sauce is formed, add the broth in a steady, but slow, stream, steadily whisking.
Bring to a gentle simmer, and simmer for a few minutes to allow it to thicken, and pour over the potato gratin.
Cover the gratin with foil, and place the baking dish on a baking sheet. Bake for 45 minutes. Test to make sure the potato slices are tender.
Uncover, sprinkle on the last of the cheese and bake for another five to ten minutes uncovered, or until the cheese is melted.
Serve piping hot.

Nutrition