The Easiest Ina Garten Onion & Fennel Soup Gratin Recipe Ever

A warm, velvety onion & fennel soup gratin offers pure comfort through its rich, deeply layered flavors that transform humble ingredients into something extraordinary.

Golden-brown caramelized onions mingle with soft, sweet fennel, creating a deeply aromatic base that feels like a culinary embrace.

French countryside traditions whisper through each spoonful of this soul-satisfying soup.

Melted Gruyère cheese blankets the surface with irresistible golden-brown complexity, adding a luxurious texture that elevates the entire dish.

Rustic and elegant simultaneously, this recipe promises a sophisticated yet approachable dining experience.

Hearty enough for a main course yet delicate in its nuanced seasoning, the soup represents culinary alchemy at its finest: transforming simple ingredients into something magical.

One Warm Goodbye From a Bowl of Onion and Fennel Bliss

Culinary journeys often begin with unexpected flavor combinations, and Ina Garten’s Onion & Fennel Soup Gratin exemplifies gastronomic brilliance.

Mediterranean warmth radiates through each spoonful, telling stories of slow-cooked caramelization and rich French countryside traditions.

Wine-infused depths create complex layers that dance between sweetness and savory intensity.

Gruyère’s melted embrace transforms simple ingredients into luxurious comfort.

Why Onion and Fennel Soup Gratin Is a Cozy Classic

• Unleash Flavor-Packed Caramelization: The slow cooking of onions and fennel creates deep, rich, nutty flavors that transform ordinary ingredients into an extraordinary culinary experience. Each golden-brown bite promises intense, complex taste sensations that dance across your palate.
• Master Elegant French-Inspired Technique: This recipe captures classic French cooking methods by layering sophisticated ingredients like sherry, Cognac, and white wine, which build incredible depth and complexity. Home cooks can easily replicate professional restaurant-quality techniques with simple steps.
• Craft a Luxurious One-Pot Comfort Meal: The soup gratin delivers a complete meal in a single dish, combining hearty broth, caramelized vegetables, and melted cheese into a comforting, warming experience. Perfect for chilly evenings or when you crave something indulgent yet straightforward to prepare.
• Elevate Weeknight Cooking with Gourmet Simplicity: Despite its impressive appearance, the recipe requires minimal technical skills and uses basic kitchen equipment. Anyone can create a restaurant-worthy dish that looks and tastes incredibly sophisticated without spending hours in the kitchen.

Everything You Need for Onion and Fennel Soup Gratin

• Onions: Sweet and aromatic base that becomes deeply caramelized for rich flavor.
• Fennel: Adds a subtle licorice-like taste and soft texture to the soup.

• Butter, Olive Oil: Helps caramelize vegetables and provides a rich, smooth cooking base.
• Sherry, Cognac, White Wine: Adds depth, complexity, and enhances the overall flavor profile.
• Beef Broth: Provides a hearty, savory foundation for the soup.

• Gruyère Cheese: Melts beautifully with a nutty, complex flavor that complements the soup.
• Bread Slice: Creates a crispy, toasted layer that absorbs the soup and adds texture.

• Bay Leaves, Salt, Pepper: Classic seasonings that enhance and balance the soup's deep flavors.

How to Build Layers in Ina’s Onion and Fennel Gratin

Step 1: Sauté Aromatic Vegetables

• Sliced onions
• Chopped fennel

Cook slowly, stirring occasionally, until vegetables caramelize to a rich golden brown (30-40 minutes). Adjust heat if needed to prevent burning.

Step 2: Deglaze with Spirits

• Sherry
• Cognac

Scrape browned bits from pot bottom. Let liquid bubble and reduce for 5 minutes. Add white wine and simmer additional 15 minutes.

Step 3: Build Soup Base

• Beef broth
• Bay leaves
• Salt
• Black pepper

Bring mixture to a gentle boil. Reduce heat and simmer uncovered for 20 minutes. Remove bay leaves and taste, adjusting seasonings.

Step 4: Prepare Cheesy Topping

• Toasted bread slice
• Generous sprinkle of Gruyère cheese

Step 5: Finish and Serve

Broil soup for 3-5 minutes until cheese melts and turns golden and bubbly. Serve immediately while hot and enjoy the rich, comforting flavors.

Tips That Make Onion and Fennel Soup Gratin Shine

• Slowly Caramelize Onions: Take your time cooking onions over low heat to transform them into a deep golden brown, releasing their natural sweetness and creating a rich flavor base for the soup.
• Select Premium Broth: Choose a high-quality beef broth that will elevate the entire dish. Homemade stock or top-tier store-bought versions will make a noticeable difference in depth and taste.
• Layer Liquor for Complexity: Adding sherry, Cognac, and white wine builds incredible flavor layers. Let each alcohol simmer to burn off harsh notes while leaving behind sophisticated undertones.
• Create Crispy Bread Croutons: Toast bread slices until they're perfectly golden and crunchy. Sturdy croutons will maintain their texture when topped with melted cheese, providing a delightful contrast to the soup.
• Perfectly Broil Cheese Topping: Monitor the cheese closely while broiling to achieve a gorgeous golden-brown, bubbling surface. The caramelized cheese creates a stunning and delicious final touch that transforms the entire dish.

Storing Ina’s Onion and Fennel Gratin Without Losing Crunch

• Freeze Wisely: Separate the soup from its cheesy topping before freezing. Pour the cooled soup into a freezer-safe container, leaving a small space at the top for expansion. This method preserves the soup's rich flavors and prevents soggy bread when you're ready to enjoy it later.
• Refrigerator Revival: Maximize freshness by storing the soup in a glass or ceramic container with a tight-fitting lid. Keep it in the coldest part of your refrigerator, typically the back shelf, to maintain its delicate flavor profile and prevent any potential flavor absorption from other foods.
• Reheating Magic: Transform your leftover soup into a piping hot meal by thawing it overnight in the refrigerator.

Fun Flavor Twists for Onion and Fennel Soup Gratin

• Vegetarian Fennel Fusion: Replace beef broth with rich vegetable stock, adding roasted mushrooms for depth. Swap Gruyère with smoked gouda for an earthy, plant-based version of the classic soup.
• Mediterranean Herb Infusion: Incorporate fresh thyme, rosemary, and oregano during caramelization. Use white wine from Mediterranean regions like Greece or Italy to enhance the herbal notes and create a more vibrant flavor profile.
• Spicy Seafood Transformation: Substitute beef broth with seafood stock and add saffron threads. Top with seared scallops or crab meat before broiling, creating a luxurious maritime-inspired soup experience.
• Rustic Autumn Comfort: Mix in roasted root vegetables like parsnips and carrots during the caramelization process. Sprinkle crispy pancetta pieces on top before broiling for a hearty, seasonal variation that celebrates fall flavors.

Ina Garten Onion & Fennel Soup Gratin Recipe

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4.7 from 9 reviews

• Total Time: 1 hour 50 minutes
• Yield: 6 1x

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Description

Ina Garten’s onion & fennel soup gratin delivers French countryside comfort with luxurious caramelized layers and melted gruyère. Hearty ingredients meld together in this elegant dish that warms souls and delights palates with sophisticated rustic charm.

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Ingredients

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Main Ingredients:

• 3 lb Spanish onions, halved and sliced ¼ inch thick (1.36 kg)
• 2 lb fennel, tops and cores removed, sliced ¼ inch thick (907 g)
• 8 cups (1.9 liters) canned beef broth

Liquid Ingredients:

• 4 tablespoons (59 ml) unsalted butter
• ¼ cup (59 ml) good olive oil
• ½ cup (118 ml) good dry sherry
• ½ cup (118 ml) Cognac or brandy
• 1½ cups (355 ml) good dry white wine, such as Sauvignon Blanc

Seasoning and Garnish:

• 3 bay leaves
• 1 tablespoon kosher salt
• 1½ teaspoons freshly ground black pepper
• 1 small sourdough or white French boule, crusts removed, sliced ½ inch thick, and toasted
• 4 to 6 ounces (113 to 170 g) Gruyère cheese, grated

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Instructions

1. Create a flavor foundation by gently sautéing diced onions and sliced fennel in a blend of butter (or 60 grams) and olive oil (or 60 milliliters) over medium heat. Allow the vegetables to slowly caramelize for 30 to 40 minutes, stirring periodically to prevent burning and develop a rich, golden-brown color.
2. Deglaze the pot with sherry (or 120 milliliters) and Cognac (or 120 milliliters), scraping the flavorful brown bits from the bottom of the stockpot. Let the alcohol reduce and concentrate the flavors for approximately 5 minutes.
3. Pour in white wine (1 or 360 milliliters) and continue simmering uncovered for an additional 15 minutes to further develop the soup’s complexity.
4. Introduce beef broth (or 1.9 liters), along with bay leaves, kosher salt (or 15 grams), and freshly ground black pepper. Bring the mixture to a robust boil, then reduce heat and allow to simmer uncovered for 20 minutes.
5. Remove bay leaves and adjust seasoning to taste, ensuring a balanced and rich flavor profile.
6. Position oven rack 5 inches (12.5 centimeters) from the broiler and preheat to high temperature.
7. Carefully ladle the hot soup into heat-resistant serving bowls, ensuring even distribution.
8. Top each bowl with a toasted bread slice and generously sprinkle with grated Gruyère cheese (4 to or 115 to 170 grams).
9. Broil for 3 to 5 minutes until the cheese melts completely, turns golden, and develops a bubbly, slightly crisp surface.
10. Serve immediately while hot, allowing guests to appreciate the deep, multilayered flavors of this classic French onion soup.

Notes

• Slow-cook onions to golden perfection, releasing their natural sweetness and creating a deep, rich base flavor for the French onion soup.
• Select premium beef broth as the foundation, ensuring a robust and authentic taste that elevates the entire dish.
• Incorporate alcohol carefully, letting sherry and white wine simmer and concentrate their complex flavor profiles without overpowering the soup.
• Crisp bread slices strategically to maintain structural integrity when floating atop the savory broth, preventing sogginess and preserving textural contrast.
• Broil cheese with precision, aiming for a bubbling, golden-brown crust that transforms the soup into a visually stunning and irresistibly delicious meal.

• Prep Time: 25 minutes
• Cook Time: 1 hour 25 minutes
• Category: Dinner, Appetizer
• Method: Simmering
• Cuisine: French

Nutrition

• Serving Size: 1 bowl ( 1.5 cups)
• Calories: 478
• Sugar: 6.4g
• Sodium: 815mg
• Fat: 24g
• Saturated Fat: 10g
• Unsaturated Fat: 9.4g
• Trans Fat: 0.5g
• Fiber: 2.3g
• Protein: 21g
• Cholesterol: 45mg