The ultimate in elegant vegetarian cuisine, Mushroom Wellington combines portobello mushrooms, spinach, and fresh herbs, all bundled in a puff pastry crust. This plant-based showstopper presents beautifully. For this reason, we like to save this one for holidays and special occasions.

How To Make This Recipe

Before starting this recipe, we clean our portobello mushrooms using lightly moistened paper towels. We remove the woody stems and slice off any excess mushroom rim that curls over the gills. Then, we pull together our remaining ingredients.

For our “egg” wash, aquafaba stands in for traditional egg whites. If you haven’t used aquafaba before, we’re quite literally referring to reserved liquid from a can of chickpeas or leftover chickpea cooking water. We continue to be amazing by the versatility of aquafaba.

Prepare Filling

We start by bringing a large skillet up to temperature over medium heat. Once our skillet is warm, we add one tablespoon of olive oil along with our onion. Then, we reduce our heat and season with salt and pepper. We want those onions to caramelize, so we allow them to cook, stirring occasionally, for about 10 minutes or until those onions brown.

Once our onions caramelize, we add our baby spinach and increase the heat to medium. We cook, stirring regularly, until our spinach wilts. Then, we transfer this mixture to a bowl and allow it to cool.

Baby spinach with caramelized onions.

Next, we return our pan to medium-high heat and add in our remaining olive oil. In our hot pan, we sear our mushrooms with the top side down. We allow these to cook until lightly golden, which takes about 5 minutes. Then, we turn them over and sear the other side. Once both sides are lightly golden, we remove our mushrooms from the from the heat and allow them to drain on a paper towel.

Drain portobello caps on a paper towel.

Before we move onto the next step, we need our spinach mixture and mushrooms to be completely cool. So, we transfer them to the refrigerator. When we’re trying to reduce our cooking workload, we often prepare our filling the day before we plan to make our mushroom wellington. This serves as a natural stopping point.

Roll It Up

Now that our filling has cooled, we’re ready to wrap everything up in puff pastry. We start by lining a baking tray with parchment paper. Then, we place a sheet of puff pastry on top. For our first layer, we spread our spinach mixture over the middle third of the pastry. We’re careful to leave an extra 3/4 inch border around the edges to allow for folding.

Next, we dress our mushrooms before placing them on to of the spinach mixture. To do so, we first spread our dijon mustard over the mushrooms. Then, we sprinkle those mushrooms with onion powder and oregano before seasoning with salt and pepper. One by one, we gently place our seasoned mushrooms on top of the bed of spinach.

Puff pastry with spinach, mushroom, and dijon.

Seasoned portobello caps on a bed of spinach ready for wrapping.

If you’ve rolled a burrito or wrapped a present, you can seal puff pastry dough. We first fold in the sides, and then we fold down the top flap. We carefully roll our pastry over the top of our mushrooms until we have a log shape. Finally, we press down to seal the edges. Then, we gently roll over the wellington so that the seam is facing down against the parchment paper before baking.

Bake Until Golden

Before we bake our wellington, we prepare our vegan “egg” wash by whisking all of the wash ingredients together in a bowl. Then, we lightly coat the puff pastry with our wash using a pastry brush. We then chill the entire loaf in our freezer for 10 minutes, or in the refrigerator for a half hour.

Next, we brush on another layer of our vegan “egg” wash. Once again, we chill the pastry. While our wellington chills, we preheat our oven. We bring our oven up to 400°F to prevent undercooked puff pastry.

Brush on the “egg” wash.

After our second round of cooling, we roast our wellington until the pastry turns golden brown and crispy.

Golden brown mushroom wellington.

Ready To Serve

Once the pastry turns golden brown, our mushroom wellington is done. We carefully remove our pastry from the oven, and we allow it to rest on the baking sheet for 10 minutes before serving.

Slice and serve your mushroom wellington.

Wondering what to serve this with? Here are a few side dishes for inspiration:

Recipe Card for Mushroom Wellington

Here’s the recipe card for Mushroom Wellington. Print, share or save!