Finely chopped mushrooms and spinach fill a sealed puff-pastry parcel with garlic, thyme and Dijon mustard. Cook the filling until its moisture has evaporated and let it cool completely before wrapping: a wet or warm filling can soften the pastry. Brush with egg, cut the three steam vents and leave the baked Wellington to rest for 10 minutes before slicing.
AI illustration: The recipe image was created with AI. The finished dish may look different.
Why you will like this recipe
- A wide skillet gives the mushrooms and onion room to lose moisture before the spinach is added.
- Dijon mustard goes into the cooled filling, and the pastry is sealed with the seam underneath.
- Brush the pastry with beaten egg and cut three small steam vents before baking.
- You can prepare and chill the filling one day ahead, then wrap it in pastry shortly before baking.
Timing: the 30-minute preparation estimate includes making and cooking the filling and wrapping it in pastry. Allow 35–40 minutes in the oven and 10 minutes resting, giving a base estimate of about 75–80 minutes, plus the time needed for the filling to cool completely. Cooling time is not fixed and is excluded from the recipe card’s 80-minute estimate. Do not wrap warm filling to fit the clock.
Timing and preparation
Preparation: about 30 minutes, including making and cooking the filling and wrapping it in pastry | Oven: 35–40 minutes | Rest: 10 minutes | Base total: about 75–80 minutes, plus complete cooling of the filling | Servings: 6
Substitutions
Use vegan puff pastry and plant milk instead of egg wash for a vegan version. Chestnuts can replace up to one-third of the mushrooms.
Ingredient choices and cooking cues
Mushrooms and spinach carry plenty of water, which makes moisture control the key to this Wellington. Finely chopped mushrooms create a filling that packs neatly without leaving large gaps. Use a wide pan and keep cooking until the liquid has evaporated; the mixture should look concentrated rather than glossy with pooled juice. Add the spinach and cook until that moisture has also disappeared.
Let the filling cool completely before it touches the puff pastry. Warm filling softens the pastry fat and can make the sheet sticky, difficult to seal and less able to rise into distinct layers. Dijon brings a tangy note to the earthy mushrooms, while thyme supports their savoury flavour. Fold these flavours into a filling that is dry enough to hold together without leaking.
Keep the pastry edges free of filling so they can seal cleanly. The seam belongs underneath, and the vents give steam a route out through the top. Look for deeply golden pastry rather than stopping at a pale surface: the base also needs to bake through. Resting before slicing helps the filling settle and makes the pastry easier to cut cleanly.
Storage and reheating
Refrigerate for up to 3 days. Reheat uncovered at 350°F (175°C) until hot and crisp.
Recipe card

Spinach Mushroom Wellington
Ingredients
Method
- Heat oil in a wide skillet. Cook mushrooms and onion over medium-high heat for 12 to 15 minutes, until the liquid evaporates.
- Add garlic, thyme, salt, and pepper for 1 minute. Add spinach and cook until dry. Cool completely, then stir in mustard.
- Heat the oven to 400°F (205°C). Place the filling down the center of the pastry, fold it over, and seal the seam and ends. Set seam-side down.
- Brush with beaten egg, cut three small steam vents, and bake for 35 to 40 minutes until deeply golden. Rest for 10 minutes before slicing.
Notes
Estimated nutrition per serving
| Nutrient | Per serving |
|---|---|
| Energy | 333 kcal |
| Protein | 8.2 g |
| Fat | 22.0 g |
| Saturated fat | 5.0 g |
| Carbohydrate (including fiber) | 28.0 g |
| Fiber | 2.4 g |
| Sugar | 3.5 g |
| Sodium | 395 mg |
Estimates are calculated from the ingredient amounts and standard food composition references, divided into the stated number of equal servings. They are not laboratory measurements. Brands, substitutions, optional additions and portion sizes can change the result. Optional toppings, extra side dishes and unspecified added salt are excluded from the base estimate.
Frequently asked questions
Can I prepare the filling before assembling?
Yes. Cool it, refrigerate it in a covered container, and check for any released liquid before wrapping. Keep the pastry chilled until assembly and use a completely cold filling so the sheet stays manageable.
Why is the bottom of my Wellington soggy?
The filling may have retained moisture, or it may have been wrapped while warm. Check for liquid in the pan before cooling it. A well-browned top cannot compensate for a filling that releases water into the base.
More recipes to try: One-Pan Mushroom Pea Couscous · Mushroom Wild Rice Soup.
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