Wild Mushroom and Leek Wellington

If you’re looking for a vegetarian main dish worthy of the Thanksgiving table, this Wild Mushroom and Leek Wellington is a lovely place to begin. A savory filling of mushrooms, leeks, shallots, garlic, herbs, and a touch of goat cheese is wrapped in flaky puff pastry and baked until crisp and golden. The result is rich, deeply flavorful, and every bit as celebratory as a traditional roast.

Serve it as the centerpiece of a vegetarian holiday meal, or offer it alongside the rest of the Thanksgiving spread for guests who would happily skip the turkey. It pairs beautifully with mushroom gravy, roasted vegetables, salads, and all the comforting sides that make the holiday table so inviting.

INGREDIENTS:

For the Filling
2 tablespoons unsalted butter
2 tablespoons olive oil
2 large leeks, white and pale green parts only, halved lengthwise, washed well, and thinly sliced
2 medium shallots, finely chopped
3 garlic cloves, minced
2 pounds mixed mushrooms, finely chopped or pulsed in batches in a food processor (such as cremini, shiitake, oyster, or maitake)
1 teaspoon kosher salt, or to taste
½ teaspoon freshly ground black pepper
1 tablespoon fresh thyme leaves, chopped
1 teaspoon chopped fresh rosemary
2 tablespoons chopped fresh parsley
2 teaspoons Dijon mustard
1 tablespoon soy sauce or tamari
1 tablespoon balsamic vinegar or dry sherry
¾ cup toasted walnuts or pecans, finely chopped
½ cup soft fresh goat cheese
½ cup dry breadcrumbs
1 egg, lightly beaten (to bind the filling; optional but helpful)

For Assembly
1 sheet all-butter puff pastry, thawed according to package directions (if using smaller sheets, you may need 2 sheets overlapped and sealed)
2 tablespoons Dijon mustard
1 egg, beaten with 1 tablespoon water, for egg wash
Flaky salt, optional
Fresh thyme leaves, optional

METHOD:
In a large skillet, heat the butter and olive oil over medium heat. Add the leeks and shallots and cook, stirring often, until softened and lightly golden, about 8–10 minutes. Add the garlic and cook for 1 minute more.

Add the chopped mushrooms, salt, and pepper. Cook over medium-high heat, stirring often, until the mushrooms release their moisture and then cook down until the pan is quite dry, about 12–15 minutes. This step is important: the filling should be concentrated and not wet, or the pastry may become soggy.

Stir in the thyme, rosemary, parsley, Dijon, soy sauce, and balsamic vinegar or sherry. Cook for another 1–2 minutes, stirring, until fragrant and well combined. Remove from the heat.

Transfer the mushroom mixture to a bowl and let it cool for about 10–15 minutes. Stir in the chopped walnuts, goat cheese, breadcrumbs, and beaten egg. Mix until evenly combined. The filling should hold together when lightly pressed. Taste and adjust seasoning if needed.

Preheat the oven to 400°F. Line a baking sheet or sheet pan with parchment paper.

On a lightly floured surface, roll the puff pastry just enough to smooth the seams and create a rectangle large enough to enclose the filling.

Transfer the pastry to the prepared baking sheet. Spread the 2 tablespoons Dijon mustard in a strip down the center, leaving a border around the edges.

Spoon the mushroom filling into a compact log in the center of the pastry, about 10 inches long. Shape it neatly with your hands or a spatula.

Fold one long side of the pastry over the filling, then fold the other side over to enclose it, brushing the seam area lightly with water if needed to help it seal. Tuck in the ends and pinch gently to seal. Turn the Wellington seam-side down.

Brush the entire surface with the egg wash. Using a small sharp knife, cut a few small slits in the top for steam to escape. If desired, decorate with pastry leaves or simple strips cut from pastry scraps. Brush those with egg wash as well.

Chill the Wellington for 15–20 minutes before baking. This helps the pastry hold its shape.

Bake for 35–40 minutes, or until the pastry is deeply golden, crisp, and cooked through. If needed, tent loosely with foil during the last 10 minutes to prevent over-browning.

Let rest for 10–15 minutes before slicing. Garnish with a few fresh thyme leaves and a sprinkle of flaky salt if desired.

Slice into thick portions and serve warm, ideally with a rich vegetarian mushroom gravy or a simple pan sauce.

YIELD: Serves 6–8

COOK’S NOTES

Mushroom choice: A mix of mushrooms gives the most interesting flavor. Cremini provide body, while shiitake or oyster mushrooms add depth and a more woodsy character.

Keep the filling dry: The success of a Wellington depends on keeping excess moisture out of the filling. Cook the mushrooms until their liquid has evaporated and the mixture looks rich and concentrated.

Make-ahead option: The filling can be made up to 2 days ahead and refrigerated. You may also assemble the Wellington earlier in the day, refrigerate it, and bake shortly before serving.

Cheese options: Goat cheese adds a lovely tang, but you could also use cream cheese, mascarpone, or even a little grated Gruyère for a different effect.

To serve vegan: Use a vegan puff pastry, omit the egg in the filling, replace the goat cheese with a plant-based cheese or a few extra breadcrumbs and nuts, and brush the pastry with non-dairy milk instead of egg wash.

SERVING SUGGESTIONS

This would be wonderful with: