Mushroom and Spinach Wellington

Cooking the mushroom filling down until it's completely dry (a duxelles) prevents the puff pastry from turning soggy in the oven.

Instructions

1. 1

   Heat the olive oil in a large skillet over medium heat. Add the onion and cook until softened, 5 minutes.

2. 2

   Add the chopped mushrooms and cook, stirring occasionally, until they release their liquid, about 8 minutes, then continue cooking until all the liquid evaporates and the mixture turns deeply golden brown and dry, another 12–15 minutes total. This concentrated mixture, called a duxelles, must be completely dry — any leftover moisture will make the pastry soggy in the oven.

3. 3

   Add the garlic and thyme and cook 1 minute until fragrant.

4. 4

   Pour in the white wine and cook, stirring, until fully evaporated, 2–3 minutes. Season with salt and pepper.

5. 5

   Add the spinach in batches, stirring until wilted, 2–3 minutes. If any liquid pools at the bottom, continue cooking until it evaporates.

6. 6

   Remove from heat and stir in the cream cheese and walnuts until well combined. Let the mixture cool completely to room temperature (warm filling will melt the butter in the pastry before it goes into the oven).

7. 7

   Preheat the oven to 400°F (200°C). On a lightly floured surface, roll out one sheet of puff pastry slightly larger. Spread the cooled mushroom filling in a log down the center, leaving a 2-inch border on all sides.

8. 8

   Brush the border with beaten egg. Roll out the second sheet of pastry and drape it over the filling, pressing the edges together firmly to seal completely — any gaps will let filling leak out during baking.

9. 9

   Trim the excess pastry, crimp the edges with a fork, and transfer to a parchment-lined baking sheet, seam-side down.

10. 10

    Brush the entire top with beaten egg and score a few decorative slits or a pattern in the top to let steam escape.

11. 11

    Bake for 30–35 minutes, until deeply golden brown and puffed.

12. 12

    Let rest for 10 minutes before slicing, to let the filling set slightly.