1/4 cup vegetable broth mixed with 1 teaspoon balsamic vinegar
2 tablespoons olive oil
1 large egg, beaten for egg wash
1/2 teaspoon sea salt
1/2 teaspoon cracked black pepper
Instructions
Heat the olive oil in a large skillet over medium-high heat. Add the chopped cremini and shiitake mushrooms, cooking them until they release their moisture and begin to brown. This process takes about 10 to 12 minutes. It is crucial to cook the mushrooms until the pan is completely dry to prevent a soggy pastry later on.
Stir in the minced shallots and garlic, cooking for another 3 minutes until softened and fragrant. Pour in the mixture of vegetable broth and balsamic vinegar, scraping the bottom of the pan to release any browned bits. Continue to cook until the liquid has completely evaporated. Season with the fresh thyme, rosemary, salt, and pepper.
In a separate small pan, wilt the spinach quickly, then place it in a clean kitchen towel and squeeze out every drop of liquid. Finely chop the dry spinach and mix it into a bowl with the toasted walnuts and the cooled mushroom mixture. Let this filling cool completely before proceeding to the assembly stage.
On a lightly floured surface, roll out one sheet of puff pastry. Place the mushroom mixture in the center, shaping it into a neat log. Lightly brush the edges of the pastry with the egg wash. Place the second sheet of puff pastry over the top, pressing down firmly around the edges to seal the filling inside. Trim any excess pastry and use a fork to crimp the edges tightly.
Transfer the Wellington to a parchment-lined baking sheet. Brush the entire surface with the remaining egg wash for a glossy finish. Use a sharp knife to gently score a decorative pattern on the top, being careful not to cut all the way through the pastry. Bake in a preheated oven at 400 degrees Fahrenheit for 25 to 30 minutes, or until the pastry is puffed and deep golden brown. Let it rest for 10 minutes before slicing.
