Mushroom Wellington

Method

1. 1Make the duxelles. Heat 1 tablespoon of olive oil in a large skillet over high heat. Add the very finely chopped chestnut mushrooms — they should be almost minced. Cook without stirring for 2 minutes, then stir and continue cooking for 8 to 10 minutes total, until all the liquid has evaporated and the mushrooms are dry and beginning to stick slightly to the pan. Add the garlic, thyme, rosemary, and soy sauce. Cook 2 more minutes. The mixture should be dark, fragrant, and very dry — this is essential. Wet duxelles make soggy pastry. Transfer to a bowl and cool completely.
2. 2Caramelize the onions and prepare the spinach. In the same pan over low heat, add 1 tablespoon of olive oil and the sliced onions with a pinch of salt. Cook slowly for 25 to 30 minutes, stirring every 5 minutes, until deeply golden and sweet. Don't rush with high heat — caramelized onions need time. Set aside to cool. In the same pan, wilt the spinach briefly over medium heat. Transfer to a clean cloth or paper towels and squeeze out as much liquid as possible. A handful of spinach should wring out to about a tablespoon of liquid. Dry spinach is critical.
3. 3Cook and cool the portobellos. Heat the remaining tablespoon of olive oil in the pan over medium-high heat. Sear the portobello mushrooms cap-side down for 4 to 5 minutes until golden, then flip and cook 3 more minutes. Transfer to a plate lined with paper towels and drain top-side up — they will release liquid as they cool. While still warm, brush the tops generously with Dijon mustard. Refrigerate everything — duxelles, onions, spinach, and mushrooms — until completely cold. Cold filling is the single most important factor in preventing soggy pastry.
4. 4Assemble the Wellington. Preheat the oven to 210°C / 410°F. Unroll the pastry sheet onto a piece of parchment paper. Spread the duxelles in a rectangle down the center of the pastry, leaving a 4 cm border on all sides. Layer the caramelized onions over the duxelles, then the spinach. Arrange the portobello mushrooms in a row on top, mustard-side up, fitting them together snugly. Roll the pastry firmly over the filling, using the parchment to help. Press the seam tightly and place seam-side down on a lined baking sheet. Tuck and seal the ends. Brush all over with the plant milk and maple syrup wash. Score the top diagonally with a sharp knife — these lines will open as it bakes. Refrigerate 10 minutes.
5. 5Bake and rest. Bake for 30 to 35 minutes until deeply golden and the pastry is visibly puffed and crisp. If the top browns too quickly, tent loosely with foil. Remove from the oven and rest for 10 minutes before slicing — this is important. The Wellington needs to settle or the filling will slide out when you cut it. Slice with a sharp serrated knife using a gentle sawing motion to avoid crushing the pastry. Serve with vegan gravy, roast potatoes, and seasonal greens.