Mushroom Wellington Recipe

Make the Filling

1. Gather the ingredients.  Position a rack in the center of the oven and heat to 400 F/200 C.

2. Prepare the farro according to package directions.

3. Spread the cooked farro on a paper-towel-lined plate to drain.

4. In a small saucepan, heat the milk until hot, but not boiling. Stir in 2/3 of the tarragon leaves. Remove from the heat and set aside to let the flavors infuse.

5. Add the butternut squash and sweet potato cubes to a medium rimmed baking sheet. Toss with 4 tablespoons of the oil and season to taste with salt and pepper.

6. Roast until tender, about 20 minutes. Remove from the oven to a paper-towel-lined plate to absorb excess moisture.

7. Remove and reserve the stalks from the portobello mushrooms. Cut the mushroom caps into 1/2-inch thick slices.

8. Heat 2 tablespoons of the butter in a large skillet over medium heat until foaming. Add the mushroom slices and cook for 3 minutes on each side. Let drain on a paper-towel-lined plate.

9. To the same skillet, add the shallot and the remaining 1 tablespoon of oil and cook until soft, about 3 minutes. Scoop the shallot out with a slotted spoon and drain on a paper-towel-lined plate.

10. Add the kale to the skillet and cook until slightly softened, about 2 minutes. Let drain on a paper-towel-lined plate.

11. Add the remaining 2 tablespoons butter to a small saucepan and melt over medium heat. Add the flour and stir with a wooden spoon to create a thick paste.

12. Strain the infused milk into the saucepan and whisk continuously until you have a smooth, thick cream sauce. Whisk for an additional 2 minutes.

13. Finely chop the reserved mushroom stalks and stir them into the cream sauce. Stir in the farro and the shallot. Season to taste with salt and pepper. Let cool.

Assemble the Wellington and Make the Sauce

1. Grease a large, rimmed baking sheet with some butter or line with parchment paper. Set aside.

2. Once the sauce has cooled, remove the pastry sheets from its packaging and carefully unroll. Cut the sheets into four rectangles 17 1/2 cm x 11 1/2 cm (about 7 x 4 1/2-inches).

3. Lay two pieces of the puff pastry onto the baking tray.

4. With the narrow end of the rectangle in front of you, lay the baby kale on the pastry leaving a 1-inch margin around the edge.

5. Spoon a thick layer of the mushroom and farro cream on top. Tuck the buttery slices of mushroom upright into the thick sauce cream working from front to back; do not worry if there are gaps.

6. Carefully place the butternut squash and sweet potatoes on and around the mushroom, filling any gaps to help the mushrooms to stay upright.

7. Pile any leftover farro cream on top. Brush the margin of the pastry with a little beaten egg.

8. Gently lay the second sheet of pastry over the top, carefully stretching it a little to enclose the filling. Use your hands to mold the pastry around the mixture into a log shape. Press the two edges together, making sure you have an approximate 2 1/2 cm rim (about 1-inch) all the way around the pastry.

9. Use the back of a fork press into the rim to make a tight seal. Trim to create a neat edge at least 2 cm deep (about 3/4-inch). You can use the cut bits of pastry to make decorative leaves, if desired. This edge can be crimped or left plain.

10. Brush the puff pastry with a generous coating of beaten egg using a pastry brush. If you are decorating with leaves, cut them out and lay on the top. Using a sharp knife, score the top of the pastry 4 or 5 times making sure not to cut right through. If you are not decorating, score a criss-cross pattern instead (scoring allows the pastry to breathe and release steam while cooking). Repeat to create the second Wellington.

11. Put the Wellingtons, uncovered, in the fridge to chill and rest for at least 2 hours. If you want to leave it overnight, loosely cover with parchment or waxed paper.

12. When ready to bake, position a rack in the center of the oven and heat to 400 F/200 C. Bake the Wellingtons until golden and well-risen, about 40 minutes. Remove from the oven and leave to rest for 10 minutes.

13. While the Wellingtons rests, finely chop the remaining tarragon leaves. In a large skillet over medium heat, add the cream and the tarragon. Stir and let the sauce bubble and reduce by a third. Serve warm with thick slices of the Wellingtons.