Leeks in Vinaigrette With Walnuts

This classic leeks in vinaigrette transforms a humble vegetable into an elegant dish that shines as both a side or appetizer. The tender leeks soak up a tangy mustard vinaigrette while toasted walnuts add crunch and earthiness that perfectly complements the delicate onion flavor.

I discovered this recipe years ago when looking for something special yet unfussy for a spring dinner party. The combination of tender leeks with the bright vinaigrette has become my signature dish that friends now specifically request when they visit.

Ingredients

• Large leeks: Look for firm stalks with bright green tops and white bottoms. Smaller leeks tend to be more tender but larger ones work beautifully when cooked properly
• Extra virgin olive oil: Use a good quality oil since it forms the base of both the vinaigrette and walnut topping
• White wine vinegar: Provides brightness and acidity that balances the sweetness of the leeks
• Dijon mustard: Adds essential tanginess and helps emulsify the vinaigrette
• Whole grain mustard: Provides texture and visual interest with its distinctive appearance
• Walnuts: Their rich buttery flavor creates the perfect counterpoint to the delicate leeks
• Fresh tarragon: The anise notes of this herb elevate the entire dish with distinctive flavor
• Garlic: Just one clove adds depth without overwhelming the other flavors

Step-by-Step Instructions

Toast the Walnuts:

Gently toast walnuts in a 350°F oven for 6 to 8 minutes until they become golden brown and fragrant. Watch them carefully as they can burn quickly. After cooling, coarsely chop them and toss with olive oil and a pinch of salt to create a luxurious walnut topping.

Prepare the Leeks:

Trim the root ends and dark green tops leaving about an inch of the green portion. Slice the leeks into half inch rounds and rinse thoroughly to remove any hidden dirt or sand. The dark green parts won't form perfect rounds but they add color and flavor to the finished dish.

Cook the Leeks:

Boil the leeks in well salted water for 12 to 15 minutes until they become incredibly tender. They should yield easily when pierced with a knife. Immediately transfer to an ice bath to stop the cooking and preserve their vibrant color. Once cooled drain well and pat dry to remove excess moisture.

Make the Vinaigrette:

Whisk together the grated garlic white wine vinegar Dijon mustard and whole grain mustard until well combined. Season with salt to taste. The vinaigrette should be punchy and bright as it will mellow when absorbed by the leeks.

Marinate the Leeks:

Arrange the leeks on a serving platter and drizzle generously with the prepared vinaigrette. Allow them to marinate for at least 10 minutes but ideally longer to fully absorb the flavors. This is what transforms them from simple vegetables to something spectacular.

Finish and Serve:

Just before serving scatter the walnut oil mixture over the marinated leeks. Sprinkle with freshly chopped tarragon and a generous amount of freshly ground black pepper. The combination of textures and flavors creates a dish that is far greater than the sum of its parts.

Pin it

The walnut oil mixture is what truly elevates this dish to something special. I learned this technique from a French neighbor who insisted that good olive oil should always be added fresh just before serving rather than cooked. She would prepare this for spring gatherings using leeks from her garden and I've never forgotten how something so simple could taste so luxurious.

Make Ahead Magic

This dish is actually better when prepared in advance. You can cook the leeks and make the vinaigrette up to a day ahead then combine them and let them marinate in the refrigerator. Just bring to room temperature before serving and add the walnut mixture and tarragon at the last minute. The leeks will absorb more flavor the longer they sit making this ideal for entertaining.

Serving Suggestions

These leeks shine as part of a composed vegetable platter alongside roasted beets grilled asparagus or marinated artichokes. They also work beautifully as a side dish with simple roasted chicken or fish. For a light lunch serve them with crusty bread a soft boiled egg and perhaps some good cheese for an elegant bistro style meal at home.

Seasonal Adaptations

While this recipe is traditionally made with tarragon you can adapt it to other seasons by changing the herbs. In summer basil or chervil work beautifully while in fall sage and thyme create a more warming profile. You can also experiment with different nuts hazelnuts work particularly well as do pine nuts or even pistachios.

Pin it

This recipe turns leeks into an unforgettable centerpiece—a simple yet elegant dish guaranteed to impress.

Frequently Asked Questions

→ Can I prepare this dish in advance?

Yes! The leeks can be cooked and marinated in the vinaigrette up to one day ahead. Simply cover and refrigerate, then bring to room temperature before serving. Add the walnut mixture, tarragon, and pepper just before serving for the best texture and flavor.

→ How do I properly clean leeks?

Leeks often harbor dirt between their layers. After cutting them into rounds as directed, place them in a bowl of water and swish them around. The dirt will sink to the bottom while the leeks float. Lift them out with a slotted spoon or strain through a colander, being careful not to stir up the settled dirt.

→ Can I substitute the walnuts with another nut?

Absolutely! Toasted pecans, hazelnuts, or even pine nuts would work beautifully in this dish. Just follow the same toasting and oil-tossing method for whichever nut you choose.

→ What can I serve with this leek dish?

This versatile side pairs wonderfully with roasted chicken, grilled fish, or a simple steak. It also works beautifully as part of a vegetable-forward meal alongside other room temperature dishes like roasted vegetables or grain salads.

→ How do I know when the leeks are perfectly cooked?

The leeks should be 'meltingly tender' after boiling for 12-15 minutes. Test by inserting a knife—it should slide through without resistance. Properly cooked leeks maintain their shape but are soft and silky in texture.

→ Can I use dried tarragon instead of fresh?

Fresh tarragon has a distinctive anise-like flavor that dried doesn't fully capture. If fresh isn't available, use about 1-2 tablespoons of dried tarragon, or consider substituting with fresh chervil, basil, or parsley for a different but complementary flavor profile.