Mushroom Wellington
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The moment you slice into this Mushroom Wellington and see those gorgeous layers inside, you’ll understand why it gets everyone talking. Flaky, golden puff pastry wraps a rich, savory filling of juicy Portobello mushrooms, balsamic caramelized onions, wilted spinach, and crunchy toasted pecans. It’s deeply flavorful and stunning enough to be the star of any table.
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I make this for Thanksgiving, Christmas dinner, and dinner parties because it delivers a beautiful, impressive centerpiece without being as complicated as it seems. It looks like something straight out of a fancy restaurant with very little effort. Store leftovers in the fridge for up to 2 days and reheat in the oven to bring the pastry back to life.
Ingredients You’ll Need
You’ll need all the ingredients shown in the photograph below.
How to Make Mushroom Wellington with Step-By-Step Instructions
Scroll down for the full recipe card containing a full printable recipe and measurements in both US customary and metric units.
There’s nothing overly complicated about making a Mushroom Wellington, and once you see how the layers come together, you’ll want to make it every time you’re cooking for a crowd.
Thaw and Prep the Puff Pastry
Start by completely thawing your vegan puff pastry, but make sure it stays cold and not warm. Cold pastry is what gives you those beautiful, distinct layers once it hits the oven, so don’t let it sit out too long.
Caramelize the Onions
Heat ½ tablespoon of olive oil in a large frying pan over medium-low heat, then add the sliced red onions and balsamic vinegar and reduce the heat to low. I use a large nonstick skillet that gives me plenty of space to cook and keeps cleanup a breeze.
Season with salt and pepper, then cook until the onions are golden brown, approximately 15 to 20 minutes, stirring occasionally. The low and slow process here builds a deep, sweet flavor that makes the filling so much more complex. Remove from the pan and set aside.
Wilt the Spinach
Return the pan to the heat and add the baby spinach, cooking until it has fully wilted. It’ll shrink down dramatically, which is exactly what you want since you need it compact enough to layer inside the pastry without making it soggy. Remove from the pan and set aside.
Sear the Portobello Mushrooms
Return the same pan to the heat and increase to medium-high. Heat the remaining 2½ tablespoons of olive oil and add mushrooms, placing them flat side down.
Cook until they are lightly browned, approximately 5 minutes, then turn them over and cook until they are golden brown, approximately 5 more minutes. Remove the mushrooms from the pan and place them on a kitchen towel until they’ve cooled.
Go ahead and pop the cooked onions and spinach in the fridge at this point, too, so nothing is going into the pastry warm.
Preheat the Oven
Preheat oven to 390°F/200°C while your mushroom filling components cool down. At the same time, line a baking sheet with parchment paper or a silicone baking mat so everything’s ready to go by the time the Wellington’s up for baking.
Assemble the Wellington
Place your thawed puff pastry sheet on the prepared sheet pan. Spread half of the caramelized onions over the middle third of the pastry, leaving a ¾-inch border. Add half the spinach on top, then half the toasted pecans, then place the mushrooms on top.
Sprinkle with the finely chopped fresh rosemary and fresh thyme leaves, then season with salt and pepper. Finish by adding the remaining onions, spinach, and roughly chopped toasted pecans on top.
Roll, Seal, and Score
Carefully and gently roll the pastry sheet over the top of the mushroom mixture until you have a log shape. Use your fingertips to press and seal the edges firmly, then turn the Wellington over so the seam sits on the bottom.
Score a crosshatch pattern on top of the pastry using a paring knife. This not only looks beautiful but also helps steam escape during baking.
Apply the Vegan Egg Wash and Bake
Melt your vegan butter and whisk in the soy milk to combine, then brush it lightly over the top of the Wellington using a silicone basting brush. Place the baking tray in the oven and bake until golden brown and flaky, approximately 35 minutes.
Serve immediately and enjoy!
If you’re bringing this vegetarian wellington to a Christmas lunch, potluck, or gathering, let it cool completely before wrapping it loosely in foil to protect the crust.
Transport it in a flat, rigid container to keep the shape intact. You can keep it warm for a few hours by carefully tucking the container in an insulated carrier or wrapping it in a thick towel.
Ingredients
- 1 sheet vegan puff pastry
- 3 tablespoons olive oil split
- 3 red onions diced
- 1 teaspoon balsamic vinegar
- Salt and pepper to taste
- 10½ ounces baby spinach
- 4 large Portobello mushrooms trimmed and cleaned
- 1 cup pecans toasted and roughly chopped
- 2 sprigs fresh rosemary chopped
- 4 sprigs fresh thyme chopped
For the vegan egg wash
- 2 tablespoons soy milk
- 2 tablespoons vegan butter
Instructions
- Completely thaw your puff pastry but ensure it is cold and not warm1 sheet vegan puff pastry
For the filling
- Add ½ tablespoon of olive oil to a large frying pan over medium low heat, then add onions and balsamic vinegar and reduce the heat to low. Season with salt and pepper and cook until the onions are golden brown, approximately 15 – 20 minutes, stirring occasionally. Remove from the pan and set aside3 tablespoons olive oil, 3 red onions, 1 teaspoon balsamic vinegar, Salt and pepper
- Return the pan to the heat and add baby spinach and cook until it has wilted. Remove from the pan and set aside10½ ounces baby spinach
- Return the pan and increase to medium high heat. Add 2½ tablespoons of olive oil and place the mushrooms flat side down and cook until they are lightly brown approximately 5 minutes, then turn them over and cook until they are golden brown, approximately 5 minutes. Remove the mushrooms from the pan and place them on a kitchen towel until they have cooled. Place the cooked onions and spinach in the fridge3 tablespoons olive oil, 4 large Portobello mushrooms
- Preheat your oven to 390°F/200°C
- Line a baking sheet with parchment paper or a silicone baking mat, and place a puff pastry sheet on top. Now, spread half of the onions over the middle third of the pastry sheet, leaving ¾ inch border. Add half the spinach on top, then half the toasted pecans, then place the mushrooms on top, then add rosemary, thyme, and season with salt and pepper. Next, add the remaining onions, spinach, and toasted pecans1 cup pecans, 2 sprigs fresh rosemary, 4 sprigs fresh thyme
- Carefully and gently roll the pastry sheet over the top of the mixture until you have a shape like a log. Use your fingertips to press and seal the edges of the log and turn it over so the seam is on the bottom
- Score a crosshatch pattern on the top of the pastry using a pairing knife
For the vegan egg wash
- Melt your vegan butter and then add soy milk and whisk to combine and brush it lightly over the top of your wellington2 tablespoons soy milk, 2 tablespoons vegan butter
- Place the wellington in the oven and bake until golden brown and flakey, approximately 35 minutes. Serve immediately and enjoy!
Notes
Nutrition
How to Store Leftovers
Let the Wellington cool completely before wrapping individual slices tightly in plastic wrap or storing them in an airtight container in the fridge, where they’ll keep well for up to 2 days.
To reheat, place slices in the oven at 350°F for about 10 to 15 minutes to bring back that crispy, golden pastry. Avoid the microwave or the pastry will turn soggy.
For longer storage, uncooked Wellington freezes well for up to 2 months. Wrap tightly, then place in a freezer-safe bag or container, and bake straight from frozen.
What to Serve With Mushroom Wellington
A dish as beautiful and savory as this deserves equally good sides. Creamy mashed potatoes or a rich mushroom gravy are absolutely delicious, classic pairings that complement the flaky pastry and the hearty filling so well.
Roasted root vegetables like carrots and parsnips, or a simple green bean almondine, add great color and texture to the plate. For something lighter, a crisp green salad with a tangy vinaigrette cuts through the rich flavors beautifully.
Grilled asparagus or garlic butter Brussels sprouts are equally stunning on a holiday table where you want a spread that feels special.
More Easy Recipes for You to Try at Home
If you love this vegan mushroom Wellington recipe, you’ll also enjoy these other mushroom dishes:
