Wild Mushroom & Watercress Truffle Aioli Recipe

Prepare mushrooms

Wipe mushrooms clean with a damp towel; trim stems and slice larger mushrooms into bite-size pieces so all pieces are roughly uniform.

Place a medium skillet over low heat. Add 1/2 cup extra-virgin olive oil and 1 tablespoon unsalted butter. Heat gently until butter melts and oil shimmers but does not smoke (about 2 minutes).

Add smashed garlic cloves and thyme sprigs to the oil to infuse for 1 minute, stirring gently to release aroma.

Increase heat to medium-low and add the prepared mushrooms in a single layer if possible. Cook slowly, stirring occasionally, until they release their moisture and become tender and slightly golden, about 8–12 minutes. Keep the heat low enough to avoid browning too quickly; the goal is soft, concentrated flavor.

Season mushrooms with 1 teaspoon sea salt and 1/2 teaspoon black pepper halfway through cooking. Continue to cook until most of the liquid has reduced and mushrooms are concentrated and glossy (another 3–5 minutes).

Remove skillet from heat. Discard thyme sprigs and smashed garlic (or finely chop and reserve if you want small flecks in the aioli). Let mushrooms cool to room temperature (10–15 minutes). Reserve any infused oil in the pan — strain and keep approximately 1 tablespoon of it to incorporate into the aioli for extra mushroom flavor.

In a medium bowl, whisk together 2 egg yolks, 1 tablespoon fresh lemon juice and 1/2 teaspoon Dijon mustard until smooth and slightly frothy.

Slowly begin to drizzle in the neutral oil in a very thin, steady stream while whisking vigorously to form an emulsion. Start with about 3 tablespoons of neutral oil—whisk until thickened and yolks have taken on a creamy texture (about 1–2 minutes).

Once the initial emulsion is stable, continue adding the remaining neutral oil and 3/4 tablespoon extra-virgin olive oil in a slow stream, whisking constantly, until the mixture reaches a thick, mayonnaise-like consistency. If the emulsion breaks, stop adding oil and whisk in 1 teaspoon warm water to bring it back together, then continue.

Whisk in 1/2 teaspoon salt, 1/4 teaspoon freshly ground black pepper, and 1/2 teaspoon black truffle oil. Taste and adjust seasoning slightly; truffle oil is potent—add no more than an extra 1/4 teaspoon if needed.

If you prefer a lighter, safer (no raw egg) version, you may substitute 3/4 cup high-quality store-bought mayonnaise for the egg-yolk emulsion; then whisk in lemon, Dijon, salt, pepper and truffle oil and proceed to the next step.

Roughly chop the cooled confited mushrooms into smaller pieces if needed so they will incorporate smoothly into the aioli (aim for 1/4- to 1/2-inch pieces).

In a small bowl, dress the watercress: combine 1 cup packed watercress with 1 teaspoon champagne or sherry vinegar and a pinch of salt; toss to lightly wilt and brighten the greens. This removes raw sharpness and preserves color.

Fold the chopped mushrooms (including up to 1 tablespoon reserved infused oil), the dressed watercress (reserve any excess liquid), and 1 tablespoon finely snipped chives into the truffle aioli base. Stir gently until evenly combined. Adjust seasoning with the remaining 1/4 teaspoon sea salt and 1/8 teaspoon black pepper, tasting as you go.

If the aioli is too thick, thin with 1–2 teaspoons of water or lemon juice to reach a spreadable consistency. Taste for truffle intensity and add up to another 1/4 teaspoon truffle oil if desired, but use sparingly.

Transfer the aioli to a jar or airtight container. For best flavor, refrigerate at least 1 hour to let flavors meld. Top with a light sprinkle of freshly grated Parmesan or Pecorino and a few extra chopped chives just before serving, if using.

Serve chilled or at cool-room temperature as a spread for sandwiches, a dip for roasted vegetables, or alongside grilled meats and fish. Keeps in the refrigerator for up to 3 days (if made with raw yolks) or up to 5 days if prepared with store-bought mayonnaise.