Baked fennel gratin combines tender roasted fennel and onions with a golden, cheesy panko crust. Finished with Gruyère, Parmesan, and a whisper of nutmeg, this elegant side dish is easy to make and a lovely accompaniment for holiday meals or weeknight dinners.
Fennel Gratin
Roasted fennel is naturally aromatic and pairs beautifully with nutty Gruyère and salty Parmesan. In this gratin, fennel wedges are gently cooked in olive oil with slices of onion, braised briefly in broth, and then finished under the broiler with a crisp topping of panko breadcrumbs and cheeses. The result is a flavorful, slightly caramelized side dish that’s impressive enough for a holiday table but simple to prepare any night of the week.
If you’re new to fennel, its mild anise-like flavor softens considerably when roasted and takes on sweet notes that complement seafood, poultry, and roasted meats. Shaved raw fennel also adds crisp texture and brightness to salads, while pureed fennel makes a refined base for soups and sauces. This gratin highlights fennel’s versatility while keeping the preparation straightforward and approachable.
What does gratin mean?
A gratin is any bake topped with a browned, crunchy layer of breadcrumbs, cheese, or both. Classic potato gratin is a popular example, but the technique works well with many vegetables, including fennel, Brussels sprouts, and winter squash.
Fennel Gratin Ingredients
- Fennel: 2 large fennel bulbs (about 3 pounds total). Remove stalks and fronds, reserving a few fronds for garnish. Trim and quarter the bulbs, removing any tough core before slicing into 1/2-inch wedges.
- Onion: 1 small yellow onion, sliced about 1/4 inch thick.
- Olive oil: 1 1/2 tablespoons to sauté the vegetables.
- Salt and pepper: Kosher salt and freshly ground black pepper to taste (about 1 1/2 teaspoons total salt used in the recipe).
- Broth: 3/4 cup vegetable or chicken broth (or use a mild stock or broth you prefer).
- Gruyère: About 2 ounces (roughly 1/2 cup) grated Gruyère cheese.
- Parmesan: About 1 ounce (roughly 1/2 cup) finely grated Parmesan cheese.
- Panko breadcrumbs: 1/3 cup for a crisp topping (gluten-free panko works as a substitute).
- Nutmeg: A pinch (about 1/8 teaspoon) of freshly ground nutmeg for warmth and balance.
How to Make Fennel Gratin
- Preheat the oven to 325°F (160°C).
- Prepare the fennel: Trim, quarter, remove any woody core, and slice the bulbs into 1/2-inch wedges. Slice the onion into 1/4-inch slices.
- Heat an oven-safe 12-inch skillet over medium-low. Add the olive oil and arrange the fennel wedges in concentric circles, tucking onion slices between them. Season with about 1 teaspoon salt and several grinds of pepper.
- Sauté gently for 4–6 minutes, shaking the pan occasionally, until the vegetables become fragrant but the oil does not smoke.
- Pour in the broth, then transfer the skillet to the preheated oven. Bake for about 45 minutes, or until the fennel is tender when pierced with a knife.
- While the fennel bakes, combine the panko, grated Parmesan, grated Gruyère, nutmeg, the remaining 1/2 teaspoon salt, and a few cracks of black pepper in a small bowl.
- When the fennel is tender, remove the skillet from the oven. Increase the oven temperature to 375°F (190°C). Evenly sprinkle the cheese-and-panko mixture over the top of the fennel.
- Return the skillet to the oven and bake another 15–20 minutes, or until the topping is golden and crisp. Let rest for 5–10 minutes, then garnish with chopped fennel fronds before serving.
Tips and Variations
- For a vegetarian-friendly Parmesan, choose a Parmesan-style cheese labeled vegetarian (made without animal rennet).
- To reduce sodium, use a low-sodium broth and adjust the added salt to taste.
- Swap the Gruyère for Emmental or a mild fontina if desired; both melt well and provide a creamy finish.
- If you prefer a deeper roasted flavor, broil the gratin for 1–2 minutes at the end, watching carefully so the topping doesn’t burn.
Serving and Storage
This gratin serves about 6 as a side dish. It pairs beautifully with roasted poultry, grilled fish, or a simple roasted chicken for an elegant, balanced meal. Leftovers will keep in an airtight container in the refrigerator for up to five days. Reheat gently in a low oven to restore crispness to the topping.
Nutrition (approximate per serving)
- Yield: 6 servings; Serving size: 3/4 cup
- Calories: 191 kcal
- Carbohydrates: 24.5 g
- Protein: 8 g
- Fat: 8.5 g (Saturated fat: 3 g)
- Cholesterol: 14.5 mg
- Sodium: 574 mg
- Fiber: 8 g
- Sugar: 12 g
Notes
If you avoid cheeses made with animal rennet, look for Parmesan and other hard cheeses marked as vegetarian. Panko gives the topping an especially light, crunchy texture, but you can use regular breadcrumbs if needed. Adjust seasoning and cheese amounts to suit your taste and dietary preferences.