Fennel Gratin Recipe

This decadent Fennel Gratin Recipe is made with thinly sliced bulbs of anise-scented fennel, pungent minced garlic, and a luxurious bath of mustard-infused heavy cream. The long, slow bake transforms the fibrous vegetable into meltingly tender ribbons beneath a bubbling, golden-brown Parmesan crust that offers a savory crunch. It is an elegant, sophisticated side dish that pairs effortlessly with roasted meats, bringing a touch of French-inspired indulgence to your holiday table.

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Fennel Gratin Ingredients

2 heads Fennel: Thinly sliced. This vegetable mellows significantly when cooked, turning sweet and silky.
2 cups Heavy Cream: The foundation of the rich sauce; do not substitute with milk, as it won’t thicken properly.
1 cup coarsely grated Parmesan: Provides a nutty, salty crust that contrasts with the sweet fennel.
1 tablespoon Mustard: Dijon is preferred for its sharp acidity which cuts through the richness of the cream.
1 clove Garlic: Minced, to aromatize the dish.
1/2 tablespoon Butter: For greasing the baking dish.
Kosher Salt: To season the layers.

How To Make Fennel Gratin

Prep the Oven and Dish: Preheat your oven to 350 degrees F (175°C). Generously rub the 1/2 tablespoon of butter over the bottom and sides of a 9 by 13-inch baking dish to prevent sticking and encourage caramelized edges.
Toss the Aromatics: In the prepared baking dish (or a large bowl if you prefer less mess), add the thinly sliced fennel, coarsely grated Parmesan, minced garlic, and 1/4 teaspoon of salt. Toss everything together with your hands until the fennel is evenly coated with cheese and garlic. Spread it out into an even layer.
Create the Cream Sauce: In a measuring jug or small bowl, whisk the mustard vigorously into the heavy cream until fully dissolved. The mustard acts as an emulsifier and adds a necessary tang to balance the dairy.
Pour and Bake: Pour the mustard-cream mixture evenly over the fennel. It should seep down between the layers. Place the dish in the preheated oven and bake for about 1 hour. You are looking for the top to be deep golden brown and bubbling, and the fennel to be completely tender when pierced with a knife.

Recipe Tips

Slicing Matters: For the most tender gratin, slice the fennel bulbs about 1/4-inch thick. If the slices are too thick, they will remain crunchy; too thin, and they may turn to mush. A mandoline slicer is the best tool for consistency.
Save the Fronds: Don’t throw away the feathery green tops (fronds). Chop them up and sprinkle them over the baked gratin for a burst of fresh anise flavor and color.
The Mustard Choice: While the recipe calls for “mustard,” smooth Dijon is the classic choice for French gratins. Whole grain mustard adds a nice texture, while yellow mustard is too vinegary and should be avoided.
Check for Doneness: Fennel can be stubborn. If the top is browning too fast but the fennel is still tough, cover the dish loosely with foil for the last 20 minutes of baking.

What To Serve With Fennel Gratin

Roasted Pork Loin: Fennel and pork are a match made in culinary heaven; the anise notes highlight the sweetness of the meat.
White Fish: Serve alongside baked cod or halibut for a sophisticated dinner.
Roast Chicken: A rich, creamy side dish perfect for elevating a simple Sunday roast.
Bitter Greens: A side salad of radicchio or arugula with lemon vinaigrette helps cut through the heavy cream.

How To Store Fennel Gratin

Refrigerate: Allow the gratin to cool completely, then cover tightly with foil or transfer to an airtight container. It will keep in the refrigerator for 3 to 4 days.
Reheat: Reheat individual portions in the microwave, or place the whole dish back in a 350°F oven for 15-20 minutes to revive the crispy cheese crust.
Freeze: Freezing is possible but not ideal, as the cream sauce may separate slightly and the fennel can become watery upon thawing. If freezing, bake from frozen and expect a softer texture.

Fennel Gratin Nutrition Facts

Calories: 380 kcal
Fat: 32g
Carbohydrates: 12g
Protein: 10g
Calcium: 350mg

Nutrition information is estimated per serving.

FAQs

What does fennel taste like?

Raw fennel has a strong licorice or anise flavor and a crunch like celery. However, when roasted or baked in cream like this, it becomes incredibly mellow, sweet, and soft, losing the sharp licorice bite.

Can I use half-and-half instead of heavy cream?

It is not recommended. Heavy cream reduces and thickens into a sauce as it bakes. Half-and-half has a higher water content and is likely to curdle or result in a watery, runny gratin.

Can I assemble this ahead of time?

Yes. You can assemble the fennel, cheese, and cream mixture in the dish, cover it, and refrigerate it for up to 6 hours before baking. You may need to add 5-10 minutes to the baking time if it goes into the oven cold.

Recipe by LuluCourse: Side DishCuisine: FrenchDifficulty: Easy

Servings

servings

Prep time

minutes

Cooking time

hour

Calories

380

kcal

A luxurious, creamy side dish featuring tender fennel baked in a garlic-mustard cream sauce topped with golden Parmesan.

Ingredients

2 heads fennel, thinly sliced
1 cup coarsely grated Parmesan
1 clove garlic, minced
1/2 tbsp butter (for pan)
1 tbsp Dijon mustard
2 cups heavy cream
Kosher salt

Directions

Preheat oven to 350°F (175°C) and butter a 9×13 inch dish.
Toss sliced fennel, Parmesan, garlic, and salt in the dish.
Whisk mustard into the heavy cream.
Pour cream mixture over the fennel.
Bake for 1 hour until bubbling and golden brown.
Let rest for 5 minutes before serving.

Notes

Use a mandoline for uniform fennel slices.
If browning too quickly, tent with foil.
Heavy cream is essential for the sauce consistency; do not use milk.
Garnish with reserved fennel fronds for a professional finish.