This fennel potato gratin, made with layers of thinly sliced fennel and potatoes, and a thick creamy white Cheddar sauce, is one of the most comforting side dishes we’ve ever experienced.
Fennel Potato Gratin
- Quick Glance
- 45 M
- 1 H, 45 M
- Serves 8
Preheat the oven to 400°F (204°C) and adjust an oven rack to the middle position. Lightly butter a broiler-safe 2-quart (1.9-liter) baking dish.
In a heavy saucepan over medium heat, melt the butter. Add the shallot and cook, stirring occasionally, until tender, 2 to 3 minutes. Stir in the garlic and cook, stirring, for 1 minute more.
Sprinkle in the flour and cook, whisking constantly, for 1 minute. Gradually whisk in the half-and-half and cook, whisking constantly, until thickened and bubbly, 3 to 6 minutes.
Remove from the heat and whisk in the cheese until it melts and the sauce is smooth, 2 to 3 minutes. Stir in the salt, pepper, and nutmeg. If your sauce seems exceptionally thick, thin it with a little additional half-and-half.
Layer the potato and fennel slices alternately in the prepared baking dish. You should have 3 to 4 layers.
Spread the cheese sauce over the fennel and potatoes and cover the dish with aluminum foil.
Bake until the potatoes are tender, 50 to 70 minutes.
Remove the gratin from the oven, adjust the oven rack to 5 inches (13 cm) from the heat, and set the oven to broil. Uncover the dish and broil until golden brown, 2 to 4 minutes.
Let the gratin rest for at least 10 minutes. Garnish with rosemary and, if desired, the snipped reserved fennel fronds.
Recipe Testers' Reviews
This gratin was a sinful treat that was ready for the table after just resting for 30 minutes. My previous experience with scalloped-type potatoes had involved pre-making the day before then portioning onto cubes or rounds that held their shape after warming up... fussy, I know...but made for great plating. This recipe presented well on the plate with defined layers that held their shape yet remained creamy with a pleasant bite of both potato and aromatic fennel, almost floral yet hearty and satisfying.
I didn’t have a 2-quart casserole dish so I used a 1.2 quart dish and 3 ramekins. I am a fan of individualized portions. The smaller dishes were more caramelized, which was not a surprise. The larger dish required an extra 10 minutes in the oven than that expected by the recipe. This leads me to believe that a 2-quart dish might have needed even extra time unless this was due to oven temperature discrepancy.
I served this with grilled flank steak and a garden salad that also included shaved fennel. We also enjoyed it the following day as a main dish with an arugula and fennel fronds salad. Definitely making this again with the revised measurements! If your favorite creamy mac and cheese had a pasta-less cousin, this gratin would be it!
This may be the best potato gratin I have ever made.
This is a relatively easy preparation and yields a very rich result. The cheese sauce has just enough complexity with the shallots and nutmeg to make the flavor profile sophisticated yet family friendly. We like fennel, so when looking at my small bulb, I also sliced up the stalk just as far as it was solid and included the chopped fronds. If your fennel was larger, that would be great because I didn’t have quite enough fennel left for the final layer. I used a mandoline to thinly slice both the potatoes and the fennel, wearing a safety glove. I layered the very thin layers of potato overlapping to be opaque, and only had potatoes when I got to the top, or fourth, layer.
I used Yukon Gold potatoes as those were the potatoes on hand and they were very satisfying but if the dish was made with a more floury potato you probably only would need 50 minutes. You can approximate half-and-half with cream and whole milk. If you’re scant on Cheddar, a portion of aged table cheese, similar to toma, or even gouda or gruyere would melt well and blend in for a small portion.
Try to not overfill the baking dish and maybe put a tray or sheet of foil on the lower shelf of the oven in case it bubbles over, and be careful when removing it from the oven before broiling, because the dish is very full with bubbling liquid around the edges. Use a spatula around the edges when you remove it from the oven to ease the crunchy edges from the dish so you get to serve them instead of scrub them off the baking dish later!!
While absolutely delicious on the evening prepared, portions of this gratin also reheat nicely in the oven in a buttered dish (I used a 350℉ oven for about 30 minutes and tenting with foil to keep it from browning too much until the last 5 to 10 minutes).
This tastes very decadent yet is made with the most modest ingredients and method.