Walnut Mushroom Wellington with Caramelized Onions (Vegan)
Walnut Mushroom Wellington with Caramelized Onions

Vegan walnut mushroom wellington with caramelized onions, the ultimate meatless main dish for your holiday table. Caramelized onions, walnuts, thyme, rosemary, mushrooms, and spinach baked with flaky pastry.

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Vegan walnut mushroom wellington with caramelized onions, the ultimate meatless main dish for your holiday table. Caramelized onions, walnuts, thyme, rosemary, mushrooms, and spinach baked with flaky pastry. Together, these ingredients gift us with a comforting dish, that’s also beautiful to look at. This is a great make-ahead main for Thanksgiving, Christmas, and all upcoming holiday parties.

This walnut mushroom wellington recipe…

  • can be prepped on Christmas Eve, and baked on Christmas Day. The same goes for Thanksgiving!
  • is a meatless main that tastes delicious.
  • super simple.
  • packed with veggies!

Ingredients for vegan mushroom wellington

  • Mushrooms: I used closed-cup white mushrooms, but use your favourite mushrooms! Portobello mushrooms or even chestnut mushrooms would work fab too!
  • Onions: White onions are my preferred onion to use in this recipe, but if you only have red onions, they’ll work too!
  • Spinach: Fresh, roughly chopped spinach. My favourite type of spinach to use is baby spinach. But use whatever you have!
  • Walnuts: Roughly chopped into smallish pieces.
  • Puff Pastry: Two sheets of puff pastry. One for the wellington, and one for the star decoration. Double check the puff pasty you’re using is vegan. And use gluten-free to transform this recipe into a gluten-free recipe!
  • Herbs: Fresh thyme and fresh rosemary.
  • Spices: Salt, black pepper, chili powder and nutmeg.
  • Garlic: Fresh garlic cloves, grated.
  • Mustard: A good quality smooth dijon mustard.
  • Olive oil: Use good quality olive oil. You could even use avocado oil or even vegan butter!
  • Nutritional yeast: This will give the vegan wellington a nice umami cheesy taste.
  • Oat milk: Just a splash, you can also use any plant milk of your choice.
  • Maple syrup: Real maple syrup is best, but as it’s only used to glaze the wellington you could get away with using whatever type you have at home.

All about the herby caramelized onions mushroom filling…

This mushroom filling is so simple and delicious to make! Start by chopping the mushrooms. Just trim a little of the stalk off, and then chop it into small chunks. I like to do this by hand but to speed up the process you can pop the mushrooms into a food processor and pulse until you get small chunks.

Next, heat oil or vegan butter in a large frying pan over medium-high heat. Add in the sliced onions and cook for 5ish minutes or until they become caramelized. The secret to quick, perfectly caramelized onions is to cook them over high heat and make sure you are consistently mixing to prevent any onion slices from burning. Turn the heat down to low, then add the garlic cloves, thyme leaves and rosemary leaves to the caramelized onions. Cook for just under a minute.

Add in the chopped mushrooms, chopped walnuts, salt, black pepper, and chili powder. Turn the heat back up to medium heat and cook for a few minutes. And very quickly, you’ll see the mushrooms release water. You want to cook everything together until all that water has evaporated. Add in the roughly chopped baby spinach and nutritional yeast. Mix, and cook until the spinach leaves have wilted and there’s no excess moisture in the pan from either the mushrooms or spinach.

Allow the filling to cool to room temperature in the pan. Sometimes to speed up the cooling process, I transfer the cooked mushroom mixture into a large bowl.

Once cooled, lay plastic wrap on your worktop, and transfer the mushroom filling onto one end of the plastic wrap. Shape the mushroom filling into a 10-inch log shape using a spatula. Very carefully, from the end with the mushroom filling, roll up until the mushroom filling is covered with plastic wrap. Transfer into the fridge for at least 1 hour. I actually like to make the filling and keep it refrigerated for a day or two before using it. Doing this really makes holiday cooking so much easier!

Shaping into a wellington….

Remove the store-bought puff pastry sheet from the fridge, 10 minutes before using. This will prevent the vegan puff pastry sheet from breaking when you open and roll it out of its packaging.

Place the puff pastry onto a baking sheet. Carefully roll the mushroom filling log onto the edge of the puff pastry. If the filling falls apart or breaks a little, don’t worry! Just patch it back together into a 10-inch log. Placing the filling on the edge instead of the center of the puff pastry gifts us with a seamless wellington. Brush all the remaining edges of the pastry with dijon mustard.

Fold over the left and right sides of the puff pastry over the filling to help secure it. Spread a little more dijon mustard over those folded edges and the rest all over the middle of the pastry. Very carefully, from the mushroom filling side, roll into a log. Pinch the seal together, and place that side facing down so it’s not visible!

Final touches…

With a sharp knife and a light hand, decorate the vegan mushroom wellington. I like to draw diagonal lines on the left bottom corner, and the right top corner. You can really draw whatever you want over the puff pastry. I then like to place the puff pastry stars all over the tops and sides of the puff pastry. Best part? They’re super easy to make and are shaped with a cookie cutter! Simple, right?!

In a small bowl, mix a little maple syrup with nutmeg and oat milk. This mixture will act like a vegan egg wash and gift this wellington with a lovely golden brown color. Pop the wellington into the oven and bake for 25-30 minutes or until the flaky puff pastry is golden.

Place the beautiful vegan wellington on a serving plate. Top with a little more thyme leaves. Slice, and serve with generous amounts of vegan gravy or cranberry sauce! And there you have it, the ultimate meat-free main for Thanksgiving dinner, Christmas dinner or any special occasion.

Once you try this vegan mushroom wellington recipe, please leave a star rating and review below! I try my best to respond to you all. Oh, and don’t forget to tag me on Instagram – I can’t wait to see your images!!

More vegan holiday recipes you’ll love…


Vegan Walnut Mushroom Wellington with Caramelized Onions

Vegan walnut mushroom wellington with caramelized onions, the ultimate meatless main dish for your holiday table. Caramelized onions, thyme, rosemary, mushrooms, and spinach baked with flaky pastry.

  • Prep Time: 10 minutes
  • Cook Time: 1 hour
  • Total Time: 1 hour 10 minutes
  • Yield: 10 people 1x
  • Category: Main Course
  • Cuisine: American
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Units Scale


  • 2 sheet puff pastry
  • 34 tbsp olive oil
  • 2 large onions
  • 56 garlic cloves
  • 1 tbsp fresh thyme leaves
  • 1 tbsp chopped fresh rosemary leaves
  • 400 g mushrooms (chopped into small-medium-sized pieces. )
  • 1 cup walnuts (chopped into small pieces. )
  • 1/21 tsp chili powder
  • salt and black pepper
  • 4 tbsp nutritional yeast
  • 34 cups spinach
  • 1 tbsp smooth dijon mustard
  • 1/2 tbsp maple syrup
  • 1/2 tsp ground nutmeg
  • 1 tsp oat milk


  1. Mushroom filling: Heat oil in a large pan over high heat. Add in the onions and cook for 5-10 minutes or until caramelized. Stirring consistently to prevent burning. Add in the garlic, rosemary and thyme. Cook for a few seconds. Add in the chopped walnuts, chopped mushrooms, salt, black pepper and chili powder. Mix and cook for around 10 minutes or until all the excess moisture has been cooked off. Add in the spinach and nutritional yeast. Cook for 5-6 minutes or until the spinach has wilted and all the excess water has been cooked off. Allow the filling to cool completely. Grab a sheet of plastic wrap, place the mushroom filling on one end and shape it into a 10-inch log. Starting with the mushroom filling side, tightly wrap it with plastic wrap. Refrigerate for at least 1 hour or up to 3 days.
  2. Preheat oven to 220°C/428°F.
  3. Decoration: With one of the puff pastry sheets, grab star cookie cutters, dust them with a little flour and cut out stars to decorate the wellington with. Pop the stars into the fridge if you're kitchen is warm!
  4. Shaping: Place the second puff pastry sheet onto a baking sheet lined with parchment paper. Grab the chilled log of mushrooms and place it on the bottom edge of the puff pastry. If it falls apart when you do this don't worry! Just reshape it into a 10-inch log. Brush dijon mustard across the other edges. Fold over the right and left ends of the pastry over the side ends of the mushroom log to help secure it. *See blog post for images. Brush more of that dijon mustard over those edges, and then use the excess mustard all over the middle. From the mushroom log side, tightly and carefully roll until you reach the other end. Press the ends together. Then seal/crimp with your fingertips or with a fork. Very carefully flip the wellington so the sealed side is facing down.
  5. Final touches: With a sharp knife and a light hand, create multiple, delicate lines in the top right corner and the bottom left corner. Place the stars all over wellington. Combine nutmeg, maple syrup and oat milk. Brush all over the wellington. Bake for 30-40 minutes. Top with a few fresh thyme leaves, and enjoy!